
H : ■ •' - ■'■%0&$'-r- 1 : .'^ v 



DEPARTMENT OF THE INTERIOR 

UNITED STATES GEOLOGICAL SURVEY 

GEORGE OTIS SMITH, DIRECTOR 



Water-Supply Paper 240 



GEOLOGY AND WATER RESOURCES 



OF THE 



SAN LUIS VALLEY, COLORADO 



BY 



C. E. SIEBENTHAL 



JHBSBSlBI 




WASHINGTON 

GOVERNMENT PRINTING OFFICE 

1910 




Qass OfS 1 Q 5 

Book lASdz 



DEPARTMENT OF THE INTERIOR 

UNITED STATES GEOLOGICAL SURVEY 
i 

GEORGE OTIS SMITH, Director 



Water -Supply Paper 240 



GEOLOGY AND WATER RESOURCES 



OF THE 



??V 



SAN LUIS VALLEY, COLORADO 



BY 



C. E. SIEBENTHAL 




WASHINGTON 

GOVERNMENT PRINTING OFFICE 

1910 









NOV 8 1910 



K 



CONTENTS. 



Pago. 

Introduction 7 

Scope of report 7 

Date of report 7 

Acknowledgments 7 

Literature g 

Geography. .' 9 

Location and character g 

Topography 10 

Drainage 12 

Hydrography 12 

Stream gagings 12 

Relation of the San Luis Valley irrigation to the volume of the Rio 

Grande in New Mexico 15 

Reservoir sites 18 

Irrigation 1 9 

Canals 19 

Pumping the "sub." 20 

Pumping the underflow 20 

Canvas flumes 21 

Climate 22 

Agriculture. 25 

Order of settlement 25 

Native vegetation 26 

Cultivated crops 26 

Methods of irrigation 27 

Geology ' 2 9 

Introductory statement 29 

The west ranges 29 

Alamosa Creek valley 30 

Cat. Creek valley 31 

Rock Creek valley 31 

West of Monte Vista 32 

Vicinity of Sauguache 32 

Age of rocks 32 

Glaciation 33 

The east ranges 34 

Stratigraphy and structure 34 

Glaciation 37 

San Luis Hills 37 

The valley 3g 

Santa Fe formation 39 

Alamosa formation 40 

Quaternary deposits 47 

Sand dunes 47 

Alluvial fans 47 

Alluvium 49 

Alkali lake deposits 50 

Geologic history of the San Luis Valley 50 

3 



4 CONTENTS. 

Page. 

Underground waters 54 

General considerations 54 

Prerequisite features of artesian system 54 

Application to the San Luis Valley 54 

Source of the artesian water 55 

Adequacy and permanency of supply 56 

Capacity 56 

Flowing wells 57 

Marginal region 57 

Alamosa and vicinity 57 

Henry station and vicinity 60 

Fountain neighborhood 62 

La Jara and vicinity 63 

Sanford and vicinity 66 

Vicinity of Los Sauces 67 

Parma and vicinity 68 

Monte Vista and vicinity 69 

Center and vicinity 71 

Lockett and vicinity 73 

Veteran neighborhood 74 

Swede Corners and vicinity 75 

Warner neighborhood 76 

Moffat and vicinity 76 

Mirage and vicinity 78 

San Isabel and vicinity 78 

Baca grant 79 

Medano ranch 80 

Calkins ranch 80 

Central or Mosca-Hooper region 81 

Occurrence of gas and colored water ■. 81 

Mosca and vicinity 82 

Hooper and vicinity 85 

Kinney ranch 88 

Jacobs ranch 89 

San Luis village 90 

Nonflowing wells 92 

Antonito 92 

Manassa and vicinity 93 

Capulin and vicinity 95 

Bowen School and vicinity 97 

Monte Vista and vicinity 98 

Del Norte 98 

La Garita and vicinity 99 

Sagauche and vicinity 99 

Villa Grove and vicinity 99 

Crestone and vicinity 100 

Baldy station and vicinity 100 

Fort Garland and vicinity 101 

Springs : 101 

Mclntire Springs 101 

Dexter Spring 102 

Other springs along Conejos River 102 

Spring Creek 102 



CONTENTS. 5 

Underground waters — Continued. Page. 
Springs — Continued . 

Russell Springs 102 

Hunt Springs 102 

Antelope Springs 103 

Medano Springs 103 

Washington Springs 103 

Chamberlain Hot Springs 103 

Valley View Hot Springs 104 

Hot Creek Springs 104 

Characteristics of the artesian basin 105 

Grouping of wells 105 

Variations in flow 105 

Seasonal variations 105 

Gradual failure of wells 105 

Sudden failure of wells 107 

Irregularities in flow from the same aquifer 107 

Variation in temperature 108 

Vertical variation 108 

Seasonal variation 110 

Quality of the water Ill 

Uses of the water 115 

Wells 116 

Well drilling , 116 

Approximate measurement of flowing wells 118 

From filled pipes. 118 

From partly filled pipes 122 

Index 125 



ILLUSTRATIONS. 



/ Page. 

Plate I. Map of San Luis Valley In pocket. 

II! A, Blanca Peak from the southwest; B, Cirque at the head of Rock 

/ Creek 10 

III. A, Lava-capped slope dipping beneath the valley west of Antonito; 

/ B, Bluff of Santa Fe formation on Alamosa Creek 30 

IV . A, "Painted Rock " Bluff on Cat Creek; B, Soda Lake 32 

V. v Willow Creek Park 34 

VI. V Synclinal valley of upper Willow Creek 36 

VII.' A, Bucher well; B, Hansen Bluff, showing stratigraphy of Alamosa 

formation 40 

VIlL Typical sand dune on Medano ranch 48 

IX* Plat of Alamosa, showing location of wells 58 

X;, A, Six-inch well on Empire Farm; B, Kinch well 60 

XL. A, Espinosa well, bored in 1888; B, Navin well, bored in 1903 74 

XILi A, Clark's gas well and storage tank; B, Hunt Springs 88 

XIII. v A, Chamberlain Hot Springs; B, Mclntire Springs 102 

Figure 1. Outline map of Colorado, showing location of San Luis Valley 9 

2. Plan of pumping plant, showing subterranean gallery 21 

3. Ideal cross section of San Luis Valley from foot of Blanca Peak to 

foot of Conejos Range 45 

4. Diagram to illustrate the structure of the artesian basin and the 

alluvial slope and to indicate the relation of the glacial moraines 

to the latter 46 

5. Plat of La Jara, showing location of wells 64 

6. Plat of Richfield, showing location of wells 65 

7. Plat of Sanford, showing location of wells 66 

8. Plat of Monte Vista, showing location of wells 70 

9. Plat of Center, showing location of wells 72 

10. Plat of Moffat, showing location of wells 77 

11. Plat of Mosca, showing location of wells 83 

12. Plat of Hooper, showing location of wells 86 

13. Plat of San Luis, showing location of wells 90 

14. Diagram illustrating flow from vertical and horizontal pipes 119 

15. Diagram illustrating method of measuring partly filled pipes 123 

6 



GEOLOGY AND WATER RESOURCES OF THE SAN LUIS 
VALLEY, COLORADO. 



By C. E. SlEBENTHAL. 



INTRODUCTION. 

SCOPE OF REPORT. 

In the preparation of this report three objects have been kept in 
view: 

1. To present such a summary of the geologic conclusions of pre- 
vious workers together with the observations of the writer as would 
give to the reader a comprehensive view of the geology of the San 
Luis Valley and the surrounding rim and enable him to understand 
the relation of the artesian basin to the geologic structure. 

2. To give a description of the artesian basin, its development, and 
its prospects. 

3. Finally, to make accessible to the reader such information in 
regard to climate, agriculture, irrigation, and water resources as is 
available and of general interest. 

DATE OF REPORT. 

The field work in the San Luis Valley was completed in 1904, and 
the report thereon was prepared in 1906. Untoward circumstances 
have intervened to prevent the publication of the report until the 
present. It is to be understood, therefore, that the description of the 
development and prospects of the artesian basin refers to conditions 
at the close of field work in 1904. 

ACKNOWLEDGMENTS. 

The writer wishes to acknowledge the cordial cooperation of the 
citizens generally and in particular that of the following persons, with- 
out whose valuable assistance this report would have materially 
suffered: Hon. W. H. Adams, Hon. E. L. Myers, Hon. J. H. Williams, 
Messrs. G. H. Adams, Frank Beckwith, M. D. Blakey, M. B. Colt, 
Oscar Fountain, A. A. Goodall, William Hansen, W. R. Hapney, 

7 



8 THE SAF LUIS VALLEY, COLORADO. 

D. W. Holman, H. J. Johnson, Stephen Kinney, Horace Means, W. O. 
Meier, A. L. Moss, D. E. Newcomb, George Newsom, Prof. L. A. 
Norland, A. Shellabarger, R. W. Shellabarger, Charles Speiser, L. B. 
Sylvester, H. C. Warner, G. M. Whitead, and others, and especially 
the officials of the Monte Vista Land Company, the Parma Land 
Company, and the various well drillers in the valley. 

Obligations are also due to Prof. W. A. Converse, of the Dearborn 
Drug and Chemical Company, of Chicago, 111., for analyses of various 
well waters, duly credited in the table of analyses, several made 
especially for this report; to Dr. W. P. Headden, of the Colorado 
Agricultural College, for various analyses of San Luis waters, also 
credited in the report; and to Mr. P. F. Lund, of the Denver and 
Rio Grande Railroad, for data concerning various wells sunk by that 
company in the valley. 

LITERATURE. 

The following references comprise the important literature relating 
to the San Luis Valley: 

GEOLOGY. 

Bagg, R. M. Some copper deposits in the Sangre de Cristo Range, Colorado. Econ. 

Geology, vol. 3, 1908, pp. 739-749. 
Emmons, S. F. Orographic movements in the Rocky Mountains. Bull. Geol. Soc. 

America, vol. 1, pp. 245-286. 
Endlich, F. M. Ann. Rept. U. S. Geol. and Geog. Survey Terr, for 1873, pp. 323- 

351; for 1875, pp. 105-175. 
Gunther, C. G. Gold deposits of Plomo, San Luis Park, Colorado. Econ. Geology, 

vol. 1, pp. 143-154. 
Hayden, F. V. Ann. Rept. U. S. Geol. and Geog. Survey Terr, for 1869, pp. 72-76. 
Hills, R. C. Orographic and structural features of Rocky Mountain geology. Proc. 

Colorado Sci. Soc, vol. 3, pp. 362-458. 
Walsenburg (No. 68) and Spanish Peaks (No. 71) folios, Geol. Atlas U. S., 

U. S. Geol. Survey. 
Siebenthal, C. E. Notes on glaciation in the Sangre de Cristo Range, Colorado. 

Jour. Geology, vol. 15, 1907, pp. 15-22. 
The San Luis Valley, Colorado. Science, new series, vol. 31, no. 802 (May 

31, 1910), pp. 744-746. 
Stevenson, J. J. U. S. Geog. Surveys W. 100th Mer., vol. 3, pp. 315 et seq.; also 

Supplement, pp. 313-319. 
Van Diest, E. C. and P. H. Notes on the geology of the western slope of the Sangre 

de Cristo Range. Proc. Colorado Sci. Soc, vol. 5, pp. 76-80. 

IRRIGATION AND HYDROLOGY. 

Carpenter, L. G. Artesian wells of Colorado and their relation to irrigation. Bull. 

Colorado Agr. Coll. Exper. Sta., No. 16. 
■ Report to the Secretary of Agriculture, on artesian wells. Sen. Ex. Doc No. 

222, 51st Cong., 1st sess., pp. 218-225, 230-231. 
Green, J. S. Ann. Rept. Colorado State Engineer, 1887-8, p. 303. 



GEOGRAPHY. 



9 



Headden, W. P. Significance of silicic acid in waters of mountain streams. Am. 
Jour. Sci., 4th ser., vol. 16, 1903, pp. 169-184. 

— The brown artesian waters of Costilla County, Colorado. Am. Jour. Sci., 

4th ser., vol. 27, 1909, pp. 305-315. 

Hinton, PvICharo J. Report on irrigation and the cultivation of the soil thereby. 
Sen. Ex. Doc. No. 41, 52d Cong., 1st sess., pt. 1, pp. 151-154. 

Holmes, J. Garnett. Soil survey of the San Luis Valley, Colorado. Field Opera- 
tions Bur. Soils, U. S. Dept. Agr., 1903, pp. 1099-1119. 

Maxwell, J. P. Ann. Rept. Colorado State Engineer, 1889-90, pp. 42 and 43. 

Newell, F. H. Eleventh Census, volume on Agriculture by irrigation, pp. 98-100 

GEOGRAPHY. 

LOCATION AND CHARACTER. 

The San Luis Valley, having an area comparable to the State of 
Connecticut, lies in the south-central part of Colorado (fig. 1), with a 




Figure 1. — Outline map of Colorado, showing location of San Luis Valley. 

narrowed southern end reaching into New Mexico about 15 miles. 
The whole length of the valley from north to south is about 150 miles 
and its greatest width about 50 miles. The San Luis Hills, a series 
of basalt-capped table-topped mountains extending from Antonito in 
the direction of Fort Garland, separate the valley into two portions. 
It is with the northern part, containing the artesian basin, that we 
have to do. This portion of the valley is limited on the east by the 
majestic Sangre de Cristo Range, on the west by the Sawatchand 
Conejos ranges, and on the south by the San Luis Hills. 



10 THE SAN LUIS VALLEY, COLORADO. 

TOPOGRAPHY. 

The accompanying topographic map is based on Hayden's geologic 
and topographic atlas of Colorado for the mountainous region, with 
the addition of certain details near the margin of the valley, but the 
valley portion is compiled by the writer from sketches in the field, 
aneroid readings, and the various railway and ditch profiles. A 
study of the map will give a very clear notion of the topography. 
The salient features are the bold Sangre de Cristo Range and the less 
abrupt Culebra Range on the east, the gentler eastward-sloping 
Sawatch and Conejos ranges on the west, the flat-topped San Luis 
Hills on the south, and the almost flat surface of the valley itself. 
As the map shows, the trough of the valley lies far east of the median 
axis — close under the Sangre de Cristo, in fact. From the trough the 
country rises to the foothills, more steeply eastward, very gently 
westward, at first not more than 3 to 6 feet to the mile, but gradually 
increasing until near the foothills the rise is quite perceptible to the 
eye. The extreme flatness of the valley is shown by the great dis- 
tances for which the canals are constructed along straight lines. The 
Prairie ditch and the laterals of the Farmer's Union canal and the Del 
Norte canal run from 10 to 25 miles on straight east and west lines, 
with branches north and south at right angles. 

So nearly level is the valley floor that its essential character entirely 
escapes one traveling over it, and it is only when brought out by a 
topographic map that it becomes clear. In such a map, however, 
the alluvial-fan structure of the valley floor is strikingly manifest. 
Each stream descending from the steeper slopes of the mountains to 
the valley has deposited its spreading fan of gravel and sand. Around 
the west and south sides of Blanca Peak (as shown in PI. II, A) these 
alluvial fans are especially prominent. They are so close together 
that they coalesce along their lateral margins to form a steep, gravelly 
alluvial slope skirting the foot of the mountain. The streams coming 
down from the west range, having a much lower gradient, can carry 
neither such heavy material nor so much of it, and as a consequence 
have built up much flatter fans, though the form of the fans is no 
doubt chiefly due to the fact that, except for the surface veneer of 
gravel and sand, they were deposited in water, as shown by the con- 
tinuity of the clay and sand beds of the Alamosa formation. How- 
ever, La Jara, Alamosa, and Cat creeks have built up pronounced 
fan deltas. But the map shows at a glance that the Rio Grande has 
built the most extensive fan of all and, for the reason given above, the 
flattest. It is also clear that the trough of the valley lies so far to the 
east because the encroaching fan has pushed it there, and that the 
sluggish character of San Luis Creek has resulted from the filling in 
of its lower course by the same agency. Conejos River has built a 
long fan partly confined between the Mogotes Mountains and the 



GEOGRAPHY. 



11 



San Luis Hills, and partly extending south of the San Luis Hills into 
New Mexico, and must have discharged or at least sent distributaries 
at times to the south of the San Luis Hills. Saguache Creek has 
likewise a fan delta, but one rather poorly developed. San Luis 
Creek, taking its source in Poncha Pass not much above the level of 
the valley itself, naturally could develop no fan. 

The streams in the valley proper have cut their valleys to various 
depths, but all are shallow. The bank of the Rio Grande at Monte 
Vista, where the oldest terrace comes to the river, is 20 or 30 feet high. 
At Alamosa the bank is from 8 to 12 feet high. The other streams 
have banks varying from a few inches to 4 or 5 feet high. 

At different places in the valley there are bluffs which are not now 
adjacent to streams but which represent the margins of abandoned 
courses of the streams in their wanderings over the alluvial fans and 
slopes after the emptying of the lake which filled the valley during 
the deposition of the Alamosa formation. Most of these are shown 
on the map. One passes through Sanford, two are near Henry sta- 
tion, and one northwest of Hooper. They vary in height, but are 
mostly not far from 10 feet. 

Stretching from Washington Springs south to the mouth of Trin- 
chera Creek is a bluff bank which culminates opposite the Hansen 
ranch and has for that reason been called the Hansen Bluff. It here 
reaches a height above the Rio Grande of 60 feet, as shown in Plate 
VII, B. The level country stretching away eastward from its top 
represents the level of the valley bottom at the time when the water 
cut down the divide in the San Luis Hills and began to drain the 
lake that originally occupied the center of the valley. The original 
course of the river was probably somewhat west of its present course, 
but the alluvial fans of the streams on the west side of the valley 
have continually pushed it eastward and caused it to undercut the 
bluff. 

The following elevations have been compiled from various sources, 
railway levels, ditch levels, and aneroid readings: 



Elevation of points in San Luis Valley. 



Feet. 

Alamosa 7, 536 

Alder 8,525 

Antonito 7,878 

Baldy 7,609 

Blanca 8,405 

BlancaPeak « 14, 390 

BowenS.H 7,660 

Carnero 7,700 

Capulin... 7,800 

Center 7,630 

Creede... 8,842 



Feet. 

Crestone 7,851 

Davenport 8,158 

Del Norte 7,870 

Dune 7,538 

Freedom P. O. 

(Morgan) 7,630 

GarnettP. O 7,598 

Garland..- 7,926 

Granger 8, 040 

Hayes 7,527 

Haywood 7, 746 



Feet. 

Henry 7,548 

Hooper 7, 555 

Hot Springs 7,746 

Hunt Springs 7,670 

La Garita P.O.... 7, 900 
La Garita ranch 

house 7,630 

La Garita station . . 7, 540 

LaJara 7,599 

LaVetaPass 9,232 

LockettP. O 7,575 



a This is the elevation given in Gannett's "Dictionary of altitudes" (Bull. U. S. Geol. Survey No. 
274, 190G, p. 141). The elevation given on the map (14,490±) was determined by the Ilayden Survey; 
Gannett's figure was recalculated from that. 



12 



THE SAN LUIS VALLEY, COLORADO 



Elevation of points in San Luis Valley — Continued. 



McGinty 

Mclntyre Springs. . 
Meadow ranch 

house 

Mirage P. O 

Mirage station 

Moffatt 

Monte Vista 

Mortimer 

Mosca 

Orient mine 

Orient station 

Parma 



Feet. 
7,660 
7,542 
7,520 

7,570 

7,670 
7,607 
7,558 
7,655 
8,094 
7,551 
8,750 
8,659 
7,606 



Feet. 

PonchaPass 9,038 

Romeo 7,725 

Round Hill 8,666 

Russell Springs 7,640 

Saguache 7,710 

Sanford 7,600 

Sangre de Cristo. . . 8, 390 

San Isabel P. O.... 7,560 

San Luis Lakes 7, 520 

Santa Fe branch 

(at state line).... 8,029 

Soldiers' Home.... 7,630 
South Farm ranch 

house 7,630 

DRAINAGE. 



Feet. 

South Fork 8,178 

Swede Corners 7, 630 

Valley View Springs 8, 390 

VeteranS. H 7,600 

Villa Grove 7,951 

Wagon Creek Junc- 
tion 8, 261 

Wagon Wheel Gap . 8, 439 
Warner (or Forbes) 

S. H 7,590 

Washington Springs 7, 534 

Willis 7,576 

Zapato 7,715 



The Rio Grande enters from the middle of the west side, pursues 
a southeasterly course to the San Luis Hills, and leaves through a 
defile in them. A number of tributary streams, notably Conejos 
River and La Jara, Alamosa, and Saguache creeks, flow down from 
the Conejos and Sawatch ranges, whose more gentle slopes give room 
for extensive drainage areas. Arms of the valley extend for some 
distance up. the courses of the Conejos, the Rio Grande, and the 
Saguache, while a long, narrow arm, extending northward to Poncha 
Pass, the upper end being known as Homan's Park, is drained by 
San Luis Creek. The surface configuration of the valley is such that 
this creek should receive all the water entering the valley on either 
side, north of the Rio Grande, but as a matter of fact most of the 
drainage, especially that of the eastern range, is lost by seepage 
before it reaches the creek, or reaches it only in flood season. The 
creek itself in its lower course develops a series of wet-weather ponds 
and finally flows into the San Luis Lakes. The old overflow drainage 
course to the Rio Grande still exists but has been so blocked and con- 
cealed by incipient sand dunes as to be very difficult to trace except 
in its general features. 

HYDROGRAPHY. 

STREAM GAGINGS. 

A gaging station has been maintained for many years at Del Norte, 
where the Rio Grande enters the San Luis Valley, and above the 
head-gate of the uppermost of the valley irrigation systems. Another 
one was maintained for a long period at Embudo, N. Mex., at the 
lower end of Embudo Canyon, into which the river flows just before 
crossing the Colorado-New Mexico line. From 1899 until 1904 a sta- 



GEOGRAPHY. 



13 



tion was also maintained at State Bridge, at the upper end of Embudo 
Canyon. This station, situated but a few miles below the cultivated 
area of the valley, was of great importance in determining the volume 
of water left in the river after the valley irrigation, and the discon- 
tinuance of this and the Embudo station is much to be regretted. 
Tables showing the monthly discharge at these stations and of Conejos 
River at Los Mogotes are subjoined. 

Discharge of Rio Grande at Del Norte, 1889-1905. 
[Drainage area, 1,400 square miles.] 



Month. 


1889. 


1890. 


1891. 


1892. 


1893. 


1894. 


1895. 


1896. 


1897. 


1898. 




Sec.-ft. 


Sec.-ft. 

a 552 

a 796 

487 

913 

4,331 

3,807 

1,515 

612 

383 

470 

478 

a 565 


Sec.-ft. 

a 990 

a 1,294 

1,280 

ol,410 

3,285 

4,146 

1,693 

663 

527 

844 

374 

6 325 


Sec.-ft. 

6 300 

6 300 

316 

1,047 

2,605 

2, 187 

740 

444 

263 

259 

360 

a 922 


Sec.-ft. 

a 966 

i, b 700 

a, 6 500 

533 

1,944 

1,749 

395 

324 

270 

263 

278 

am 


Sec.-ft. 

al,003 

a 995 

a 831 

699 

1,798 

802 

292 

309 

286 

289 

236 

288 


Sec.-ft. 

i801 

a 953 

.638 

a 1,883 

2,116 

2,209 

958 

720 

454 

435 

353 

a 1,008 


Sec.-ft. 

a 1,293 

a 1,258 

a 1,081 

1,484 

2,374 

821 

403 

261 

477 

469 

310 

375 


Sec.-ft. 

a6l,000 

o6i,000 

i61,000 

1,067 

3,537 

3,391 

1,108 

475 

631 

1,472 

665 

168OO 


a 
°> 

a 


ec.-ft. 
6 1,377 






6 1,472 






61,471 






H,912 






2,722 






4,390 


July 




1,643 






509 






319 


October 

November 

December 


6 278 
319 
281 


259 

1816 

6 1,300 


Mean 


292 


a 1,242 


1,403 


812 


a 714 


a 652 


a 1,044 


a 884 


1,346 


a 1,517 






900,926 


1,014,426 


590,219 


516,886 


471,408 


754,931 


641,017 


945,418 


1, 


094,950 










1899. 


1900. 


1901. 


1902. 


1903. 


1904. 


1905. 


Mean. 


Equiv- 
alent 

in acre- 
feet. 


Mean run-off. c 


Month. 


Sec- 
ond- 
feet 
per 

square 
mile. 


Depth 

in 
inches. 


January 

February 


Sec.-ft. 

o 1,308 

il,113 

a 875 

617 

1,378 

1,091 

703 

598 

365 

492 

490 

a 742 

814 


Sec.-ft. 

a 862 

a 1,005 

399 

419 

2,854 

2,691 

547 

231 

256 

343 

253 

a 755 


Sec.-ft. 
800 
900 
500 
710 
2,570 
1,782 
594 
464 
446 
262 
283 
366 


Sec.-ft 
381 
412 
438 
638 
1,169 
618 
152 
180 
206 
242 
249 
547 


Se 

2 
5 
1 


c.-ft. 
895 

938 
755 
748 
,829 
,189 
,655 
526 
515 
349 
390 
494 


Sec.-ft. 
895 
938 
755 
652 

1,158 
716 
336 
689 
692 

1,449 
390 
494 


Se 

3 
6 
1 


C.-ft. 
895 
938 
755 
760 
,411 
,090 
,091 
578 
376 
430 
390 
494 


Sec.-ft. 

895 
938 
755 
968 
2,505 
2,605 
864 
474 
404 
506 
390 
494 


55,031 
52,094 
46,423 
57,600 
154,026 
155, 008 
53,125 
29, 145 
24,040 
31,113 
23,206 
30,375 


0.639 
.670 
.539 
.691 
1.79 
1.86 
.617 
.339 
.289 
.361 
.279 
.353 


0.737 
.698 
.621 




.771 




2.06 




2.08 


July 


.711 


August 

September 

October 

November 

December 


.391 
.322 
.416 
.311 

.407 


Mean 


a 884 


806 


436 


1 


,274 


764 


1,351 






.702 


9.525 












589,293 


641,017 


583,271 


315.790 


920,561 


553.019 


957,738 




711,186 



























i Probably too high because of ice piling up along the sides of the stream and thus narrowing the channel. 
It is not likely that the winter flow is ever more than 600 second-feet. The totals are carried out, however, 
as though the observations gave a correct idea of the discharge. 

6 Approximate. 

c The run-off given is for average months and the totals for an average year as calculated from all obser- 
vations and estimates. 



14 



THE SAF LUIS VALLEY, COLOKADO. 

Discharge of Rio Grande at State Bridge, 1899-1905. 
[Drainage area, 7.695 square miles.] 





1899. 


1900. 


1901. 


1902. 


1903. 


1904. 


1905. 


Mean. 


Equiv- 
alent 

in acre- 
feet. 


Mean run-ofi. 


Month. 


Sec- 
ond- 
feet 
per 
square 
mile. 


Depth 

in 
inches 




Sec.-ft. 


Sec.-ft. 

638 

759 

583 

350 

1,430 

1,424 

29 

22 

31 

37 

155 

571 


Sec.-ft. 

594 

581 

365 

278 

1,680 

1,032 

82 

60 

50 

54 

72 

337 


Sec.-ft. 

521 

758 

549 

315 

490 

114 

22 

17 

26 

32 

30 

37 


Sec.-ft. 

25 

25 

34 

314 

2,012 

6,375 

1,178 

47 

90 

64 

213 

302 


Sec.-ft. 

306 

417 

123 

153 
21.5 
20.3 
17.5 

140 

196 
1,590 

416 

867 


Sec.-ft. 

970 
1,195 

870 

744 
6,494 
8,531 

258 

154 
62.6 
98.3 

216 

516 


Sec.-ft. 

509 

622 

421 

359 
2,021 
2,916 

233 
• 70.4 
79.7 

284 

194 

421 


31,297 
34, 544 
25, 886 
21,362 
124, 266 
173, 514 
14,327 
4, 329 
4,743 
17,462 
11,544 
25, 886 


0.066 
.081 
.055 
.047 
.263 
.379 
.030 
.0091 
.010 
.037 
.025 
.055 


0.076 






.084 






.063 






.052 


May 




.303 






.423 


July 

August 

September 

October 

November 

December 


42 
53 
102 
117 
259 
318 


.035 
.010 
.011 
.043 
.028 
.063 


Mean 


148 


502 


432 


243 


890 


356 


1,676 


a 678 




.071 


1.19 


Acre-feet, total. 


54,069 


362, 304 


312.513 


173, 518 


642, 607 


259,200 


1,210,000 




489, 160 















a The mean obtained is the mean of the monthly means for the entire period. 
Discharge of Rio Grande at Embudo, N. Mex., 1889-1893 and 1895-1903. 
[Drainage area, 10,090 square miles.] 



Month. 

/ 


1889. 


1890. 


1891. 


1892. 


1893. 


1895. 


1896. 


1897. 




Sec.-ft. 

431 

473 

784 

2,261 

3,430 

2,922 

471 

206 

212 

283 

366 

542 


Sec.-ft. 

437 

553 

682 

2,083 

4,960 

4,107 

1,593 

814 

545 

562 

616 

648 


Sec.-ft. 

586 

616 

917 

2,370 

5,965 

5, 040 

2,356 

933 

469 

1,681 

778 

553 


Sec.-fl. 

497 

596 

1,051 

2,979 

4,890 

3, 146 

538 

191 

152 

202 

317 

324 


Sec.-ft. 

332 

415 

501 

1,436 

3,119 

2,533 

226 

230 

287 

363 

330 

320 


Sec.-ft. 

475 

503 

759 

2,541 

2,679 

3,021 

1,335 

1,080 

636 

494 

611 

534 


Sec.-ft. 
532 
551 
957 
1,797 
1,598 
367 
299 
249 
228 
349 
395 
414 


Sec.-fl. 
394 




408 




561 




1,698 




5,443 




4,621 


July 


1,274 




338 




344 




1,538 




1,138 




551 








1,032 


1,467 


1,855 


1,240 


841 


1,222 


645 


1,497 






Acre-feet, total 


747, 070 


1,064,377 


1,348,217 


S99, 730 


608, 996 


885, 279 


467, 960 


1,107,818 



Month. 


1898. 


1899. 


1900. 


1901. 


1902. 


1903. 


Mean. 


Equiva- 
lent in 
acre-feet. 




Sec.-ft. 

488 

471 

695 

2,240 

2,149 

3, 480 

2,566 

478 

338 

283 

357 

339 


Sec.-ft. 
470 
481 
761 
1,090 
956 
249 
297 
236 
309 
356 
535 
478 


Sec.-ft. 
508 
521 
581 
513 
2,323 
2,814 
289 
179 
250 
248 
327 
363 


Sec.-ft. 
341 
466 
518 
628 
3,461 
1,714 
398 
451 
359 
331 
359 
423 


Sec.-ft. 
430 
462 
532 
661 
798 
440 
. 158 
246 
228 
231 
231 
264 


Sec.-ft. 

317 

375 

788 

987 

2,574 

8,974 

1,506 

334 

348 

323 

434 

283 


Sec.-ft. 

446 

492 

720 

1,663 

3,168 

3,102 

950 

426 

336 

517 

485 

431 


27, 423 




27, 324 




44, 271 




98, 955 




194, 793 




184, 582 




58,413 




26, 194 




19, 993 




31,789 




28,860 




26, 501 








1,157 


518 


743 


787 


390 


1,437 


1,061 










838,166 


375, 138 


537, 381 


572,153 


282, 032 


1,036,600 




769, 098 









GEOGBAPHY. 

Discharge of Conejos River near Los Mogotes, 1899-1905. 
[Drainage area, 282 square miles.] 



15 



Month. 


1899. 


1900. 


1901. 


1902. 


1903. 


1904. 


1905. 




Sec.-ft. 


Sec.-ft. 
a 144 


Sec.-ft. 


Sec.-ft. 


Sec.-ft. 


Sec.-ft. 


Sec.-ft. 










6 436 
1.291 
2,323 
645 
173 
157 
138 


283 
509 
320 
76 
316 
233 
515 


297 






el, 087 
d467 






1,544 


Tune 








2,226 










528 




«76 


/33 






213 








87.4 












71.5 




g70 


























73 


433 

































a March 28. 
b April 17-30. 



cMay 11. 
d June 23. 



e August 25. 
/ August 17. 



g November 28. 



RELATION OF SAN LUIS VALLEY IRRIGATION TO THE VOLUME OF THE 
RIO GRANDE IN NEW MEXICO. 

At this point it may not be amiss to call attention to some facts 
bearing on the interstate relations of irrigation in the San Luis Val- 
ley. Agriculture and irrigation spread up the Rio Grande valley 
from Mexico and Texas, through New Mexico to the San Luis Valley 
in Colorado. With the rapid expansion of irrigation in the San Luis 
Valley the water of the Rio Grande was largely withdrawn in Col- 
orado, to the alleged great detriment of agriculture on the lower 
course of the river. The question of prior rights to the use of the 
water became a subject for interstate and international discussion. 
Major Powell in 1890, testifying before the Senate Special Committee 
on Irrigation and Reclamation of Arid Lands,* said: 

Passing into New Mexico, then, the water that practically heads in the high moun- 
tains of Colorado is largely, almost wholly, cut off from the Rio Grande, so that no por- 
tion of the water that heads in these mountains where there is great precipitation will 
cross the line into New Mexico (in the dry season) * * *. In a dry season nothing 
can be raised in the lower region and sometimes dry seasons come two or three together. 

Nevertheless, Major Powell argued that it is advantageous that the 
water in a stream be used for irrigation as near to its source as possi- 
ble, since there the duty of water is greatest and the loss from evapo- 
ration and seepage is least. 

In the valley of the Rio Grande the greater portion of the water during the season of 
irrigation is lost in the sands, as in the valley of the Arkansas. If the water of the Rio 
Grande is compelled to flow across the line from Colorado into New Mexico, it will 
destroy from 1,000,000 to 1,500,000 acres of agriculture above in order to save 200,000 
or 300,000 acres in the valley below. 

Major Powell urged that the tributaries of the Rio Grande below the 
Colorado-New Mexico line would, if the water were conserved, fur- 

oRept. Special Committee of the U. S. Senate on Irrigation and Reclamation of Arid Lands, vol. 4, pp. 
17-33. 



16 



THE SAN LUIS VALLEY, COLORADO. 



nish a sufficient flow to maintain the irrigation of that section as then 
developed. He pointed out that "when the river emerges into the 
valley at the foot of Embudo Canyon it is a fine stream and must 
always he so whatever water is taken out in Colorado above" (italics mine) . 
That this somewhat startling and paradoxical statement is borne out 
by the facts is indicated in the following paragraphs, where the expla- 
nation is suggested. 

The table on page 20, giving the comparative acreage irrigated 
from the Rio Grande and its tributaries in 1889 and 1899 shows, an 
increase in that period of over 100 per cent, yet the discharge of the 
Rio Grande at Embudo (table, p. 14) shows no corresponding sys- 
tematic diminution during the irrigation months, notwithstanding 
that the water is almost wholly removed from the river in its course 
through the valley, as shown by the gage at State Bridge. The fol- 
lowing table of the comparative discharge at Del Norte, State Bridge, 
and Embudo for 1900 to 1903, inclusive, the period for which we have 
data from all three points, brings out the fact clearly: 

Comparative discharge, in second-feet, of the Rio Grande at Del Norte, State Bridge, and 

Embudo, 1900-1903. 



1900. 



Del Norte. 



State 
Bridge. 



Embudo. 



1901. 



Del Norte. 



State 
Bridge. 



Embudo. 



January 

February 

March 

April 

May 

June 

July 

August 

September 

October 

November 

December 

Total acre-feet 



862 

1,005 

399 

419 

2,854 

2,961 

547 

231 

256 

343 

253 

755 



638 

759 

583 

350 

1,430 

1,424 

29 

22 

31 

31 

155 

571 



508 
521 
581 
513 
2,323 
2,814 
289 
179 
250 
248 
327 
363 



800 
900 
500 
710 
2,570 
1,782 
594 
464 
446 
262 
283 
366 



594 

581 

365 

278 

1,680 

1,032 

82 

60 

50 

54 

72 

337 



341 

466 
518 
628 
3,461 
1,714 
398 
451 
359 
331 
359 
423 



641,017 



362, 304 



537, 381 



583, 271 



312,518 



572, 153 



Del Norte. 



State 
Bridge. 



Embudo. 



Del Norte. 



State 
Bridge. 



Embudo. 



January 

February 

March 

April 

May 

June 

July 

August 

September 

October 

November 

December 

Total acre-feet 



381 
412 
438 
638 
1,169 
618 
152 
180 
206 
242 
249 
547 



521 

758 

549 

315 

490 

114 

22 

17 

26 

32 

30 

37 



430 
462 
532 
661 
790 
440 
158 
246 
228 
231 
231 
264 



748 

2,829 

5,189 

1,655 

526 

515 

349 



25 

25 

34 

314 

2,012 

6,375 

1,178 

47 

90 

64 

213 

302 



317 
375 

788 

987 

2,574 

8,974 

1,506 

334 

348 

323 

434 

283 



173,518 



282, 032 



920,561 



642, 607 



1,036,600 



GEOGEAPHY. 17 

Comparison of the measurements at Del Norte with those at 
Embudo for the whole period from 1890 to 1903, inclusive, shows 
further that the river as it is discharged from the canyon is very 
nearly of the size that it is at Del Norte. That is to say, during the 
season of low water there is added to the river, in the course of its 
passage through the canyon a volume nearly equal to that of the 
river at Del Norte. Examination of the topography of the country 
shows that no tributaries of any consequence come into the canyon 
from the west and from the east, but six small creeks flow into it, 
namely, Costillo, Colorado, San Cristobal, Los Montes, and Pueblo 
creeks and Arroyo Hondo. These are all short, with high gradients, 
and head in the range just east. Even in flood they carry no such 
volume of water as the Rio Grande at low stage; but the season 
alluded to was that of low water, and during such times all the water 
in these creeks is practically exhausted in irrigating the bottoms 
adjacent to them. The increment to the river in the Embudo Can- 
yon must be explained in some other way. A. L. Fellows, formerly 
United States hydrographer in charge of work in Colorado and New 
Mexico, has noted the occurrence of large springs in the canyon 
above Embudo station and has suggested that the San Luis arte- 
sian basin finds an outlet in this way. No description of these 
springs is extant, and their location, size, and number are unknown. 
The strata which go to make up the Conejos Mountains and the San 
Luis Hills form an alternating series of gravel beds and lava flows, as 
will be shown more in detail on a later page. At the south rim of the 
valley, where the water-bearing beds of the valley abut against the 
San Luis Hills, a great many springs come up along the contact, among 
them the Mclntire Springs (PI. XIII, B) with a flow of over 20 cubic 
feet per second. It is reasonable to suppose that other water-bearing 
beds in contact with the interstratified gravel beds of the older 
formation will communicate their water to those gravel beds and that 
the Rio Grande itself may do likewise, and that this water may be 
poured into the canyon at different points above Embudo. The 
increment thus gained is apparently not less than 150 second-feet and 
possibly is considerably more, the exact amount being difficult to 
determine owing to irregularities in the record. For instance, in the 
winter months the record occasionally shows more water at State 
Bridge than at Embudo, which naturally seems impossible, there 
being no known source of loss between the two stations. The error 
probably arises from encroaching shore ice, which causes too high 
gage readings at State Bridge, where the channel is narrow. 

Experiments have shown that the movement of water underground 
in sand and gravel beds is very slow, usually 1 or 2 miles per annum, 
certainly not over 3 in the extreme case. This being so, it follows 
42120°— wsp 240—10 2 



THE SAN LUIS VALLEY, COLOKADO. 

that the supply from springs in the canyon, if derived from the 
aquifers in the San Luis basin, is practically constant, since the 
amount delivered in any period of time is not dependent upon the 
rainfall during the same period, because the water rising in the springs 
has been percolating slowly underground for many years before it 
reaches the surface. Further, the principal intake of the artesian 
system on the Rio Grande is well toward the edge of the valley, 
between Del Norte and Monte Vista, above the head-gates of all but 
one of the main canals, and as this canal has a later priority than one 
below the catchment area, it follows that the artesian basin has the 
first call upon the flow of the Rio Grande and of the other streams 
as well. That this supply is exacted is shown by the fact that 
there is no annual variation in the head of the wells which just reach 
the surface along the margin of the area of flowing wells. These 
facts bear out Powell in the statement quoted at the beginning of this 
discussion that the flow of the Rio Grande below the Embudo Canyon 
will always be largely independent of the flow at the head of the 
canyon. Thus the sands and gravels of the San Luis Valley act as a 
natural reservoir with lasting benefit to the Rio Grande valley below. 

RESERVOIR SITES. 

The great excess of water wasted during the flood season and the 
frequent lack of water when needed have turned attention to the 
possibility of reservoirs in the upper" courses of the streams to 
conserve the flood water and have led to search for available sites. 
Naturally those first sought are the ones requiring the least expendi- 
ture of money to make them available. The head branches of most 
of the larger streams emptying into the valley held glaciers of various 
size during past ages, and many of the morainic dams and terraces 
resulting from glacial action offer tempting sites for storage reser- 
voirs. Such formations require most careful testing, because from 
the nature of their material they will not, as a general rule, hold water 
after it has accumulated in volume sufficient to cause much pressure.. 
But doubtless there are numerous sites in the various streams that 
will serve admirably. Such are reported on Alamosa Creek and in 
the upper course of the Rio Grande. One of those on the Rio Grande 
has been thoroughly tested b}^ the company operating the Rio Grande 
and Monte Vista canals, and a reservoir is now under construction. 

The high gradient and the small drainage areas of the streams 
coming down from the Sangre de Cristo Range preclude the establish- 
ment there of any but small irrigation systems. On the other hand, 
the low gradient and larger drainage areas of the streams entering 
from the west side of the valley are very advantageous to large sys- 
tems. Toward their headwaters these streams branch out and their 



GEOGRAPHY. 



19 



valleys take on the rolling character of glaciated cirques and are 
heavily covered with pine and spruce, as shown in the typical view 
of upper Rock Creek (PI. II, B) . The timber, by checking the run- 
off in time of heavy rains and by protecting the snow from rapid 
melting, controls the discharge of the streams and to that extent does 
away with the necessity for storage reservoirs. 

In accordance with a recommendation of the United States and 
Mexican International Boundary Commission in 1896, the Secretary of 
State requested the Secretary of the Interior to withdraw from entry 
all reservoir sites in the Rio Grande drainage area and to suspend 
action on all applications for rights of way for canals through public 
lands. Such action was accordingly taken December 5, 1896. 
Recently, upon the suggestion of the United States Reclamation 
Service, this order has been suspended in so far as it relates to bona 
fide applications made under the state law prior to March, 1903, 
when the Reclamation Service took up the Rio Grande project. 
From that date, of course, the project has the priority. The pro- 
posed reservoir at Engle, N. Mex., will have a storage capacity of 
2,000,000 acre-feet, irrigating 180,000 acres, and will be capable of 
storing all the flood waters of the Rio Grande from year to year. 

IRRIGATION. 

Canals. — The full flows of all the streams entering the valley are 
appropriated for purposes of irrigation. The Rio Grande is the main 
source of supply. The following table shows the total appropriations 
and dates of the main priorities of the principal canals and ditches 
taking water from that stream, as decreed by the courts in 1900: 

Water appropriated for principal ditches and canals from the Rio Grande, and total decreed 

appropriation. 



Priority. 



Canal. 



Appropria- 
tion. 



874 and 1879 

881 and 1891 

882 and 1889 
882 and 1890 



Centennial ditch 

Rio Grande (Del Norte) canal 

Monte Vista (Citizens') canal 

Empire canal 

San Luis Valley canal 

Costilla ditch 

Prairie ditch 

Farmers' Union canal 

Total for principal ditches and canals . 
Total appropriation decreed by court to 1900 



Cubic fed. 

82.4 
905.0 
257.8 
667.5 

92.9 
103.3 
105.1 
138.8 



2, 353. 4 
3, 022. 59 



The foregoing table, when compared with the table giving the 
average monthly flow of the Rio Grande from April to September, 
inclusive, for sixteen years (p. 20), shows that the waters of this 
stream are greatly overappropriated, even in the flood season. 



20 THE SAN LUIS VALLEY, COLORADO. 

Average monthly discharge of the Rio Grande at Del Norte, 1890-1905. 

Second-feet. 

April 968 

May .... 2,505 

June 2, 605 

July 864 

August 474 

September. 404 

Acres irrigated from the Rio Grande and tributaries, a 



County. 


1899. 


1889. 


Per cent 
increase. 




1,339 


1,389 
2,640 
52,453 
21,797 
25,918 
46,273 










75,909 
71,325 
50,290 
98, 486 


44.7 




227.2 




94.0 




112.8 








299, 989 


147, 830 


102.9 



a Census Bulletin 177, 1902, p. 14. 

This acreage is confined to the San Luis Valley, except perhaps 
10,000 acres lying on the upper courses of the river or its tributaries. 

The total area of the irrigated land in same region for 1902 is given 
by the Bureau of the Census as 303,985 acres. This shows no mate- 
rial increase over 1899. Later figures are not available. 

Pumping the u sub." — Between Mosca and Hooper is a region in 
which the supply of ditch water for several years has been inadequate, 
and here was developed the scheme of installing a gasoline pumping 
plant and pumping from the underground water level as raised and 
maintained by subirrigation. No change in the application of the 
water thus gained was proposed. It was to be used in subirrigating; 
that is, the level of underground water was to be raised by adding to it 
water taken from it — another statement of the problem of raising 
one's self by one's boot straps. The application of the water might 
be changed by the substitution of surface irrigation for subirrigation 
methods, thus doing away with the necessity of keeping up the 
underground water level; but a difficulty appears in that case. The 
interesting question is raised as to the right of one person to lower 
the water level when his neighbors, in the customary practice of irri- 
gation, are under the necessity of keeping it up. 

Pumping the underflow. — Many of the smaller streams on either side 
of the valley run out into the valley during the flood season but during 
the remainder of the year, except for short intervals, disappear 
beneath the gravel, where they emerge from the mountains at the 
upper edge of the alluvial slope. But by digging down a few feet in 

a Bulletin 16, Irrigation in the United States: 1902, p. 55, 



• GEOGRAPHY. 



21 



the rocky channels of such streams a persistent and heavy underflow 
is encountered. It is possible by installing a gasoline pumping outfit 
to raise this underflow and irrigate successfully when the water is not 
running in the streams. One such pumping outfit has been in suc- 
cessful operation in 1903 and 1904 by Mr. K. Eilinghoff 2 miles east 
of Chamberlain Hot Springs. The equipment consisted of a Si-horse- 
power gasoline engine and a 2-inch centrifugal pump with a normal 
discharge of 125 gallons per minute. The water was taken from a 
well 16 feet deep, in which the water stood within 7 feet of the surface 
but with steady pumping sank to 11 feet from the surface, where it 
remained. 

The cost of installing such an outfit is not large, and the cost of oper- 
ation for the short time it would ordinarily be in use, at critical periods 
in the growth of the crop, will also be small, so that there seems to be 
a genuine need for such plants, particularly in the northern portion of 




Figuee 2. — Plan of pumping plant, showing subterranean gallery. 

the valley and wherever else the supply of ditch water is short and the 
underflow sufficient. 

Where the underflow may not be adequate with a simple well, a sub- 
terranean gallery will be found more efficacious. The accompanying 
plan (fig. 2) of the city pumping plant of Castle Rock, Colo., may be 
advantageously copied in designing outfits of this sort. 

Canvas flumes . — Along the west slope of the Sangre de Cristo Range 
many streams afford water that is sufficient to irrigate small tracts 
but in the irrigation season is entirely lost in passing over the alluvial 
slope at the foot of the range. A plan adopted by the placer miners 
of Alaska, and used in irrigation in California, might possibly be 
worked here to advantage. At some places in Alaska water is carried 
on the surface of the ground for miles in a flume made by sewing 
together the two sides of a strip of cotton duck canvas, making a long 
canvas pipe. Or the bottom of a ditch may be lined with such canvas. 



22 THE SAN LUIS VALLEY, COLOEADO. 

The cloth will be less subject to damage by cattle and rodents, how- 
ever, when sewed up in the form of a hollow cylinder and filled with 
water. Such a flume might conceivably last for several irrigation 
seasons of a couple of months each. A subsurface dam across the 
canyon near its discharge upon the alluvial slope would help by bring- 
ing all the underflow of the stream to the surface at the intake of the 
flume. 

CLIMATE. 

The most prominent feature of the climate of the San Luis Valley 
is the prevalence of sunshine. Records are not at hand to show this 
fact with exactness, but, except for short intervals each day during 
the brief summer showery season and other rare occasions, sunshine 
prevails throughout the year. Taken in conjunction with the dry, 
rarefied atmosphere at this altitude, which allows a large amount of 
the sun's heat to reach the earth's surface and permits rapid radiation 
therefrom, this sunniness acts to relieve the worst extremes of day- 
time temperature. On the hottest days it is cool in the shade, and 
on the very coldest days it is comfortable in the sunshine. 

The most disagreeable feature of the climate is the southwest wind, 
which occasionally blows steadily for several days at a time, picking 
up the sand and driving it onward with the force of a sand blast. 

The following tables of temperature and precipitation are based 
upon observations at each of the towns named for the period indi- 
cated. The value of such observations is strictly in proportion to 
the interval of time that they cover. The records which are thus of 
greatest value are those taken at San Luis, Saguache, Garnett, and 
especially the temperature records at Fort Garland, though those 
from Monte Vista and Wagon Wheel Gap are also complete enough 
to be of interest. The data included in these tables were furnished 
by the United States Weather Bureau, and, except the Fort Garland 
observations, through Mr. F. H. Brandenburg, district forecaster at 
Denver, Colo. The temperatures in the tables, as elsewhere in this 
report, are expressed in degrees Fahrenheit. 

The observations at Fort Garland, covering a period of thirty years, 
with a short interruption in 1864-1866 and entirely antedating the 
other observations in the valley, are of especial interest because of 
their length and the opportunity they afford for comparison. For 
the period 1852-1858, inclusive, the observations were made at Fort 
Massachusetts, in the valley of Ute Creek, a short distance above the 
present site of Fort Garland, where the military post was removed in 
1858. 



GEOGRAPHY. 

Average monthly temperature at stations in San Luis Valley. 
[Degrees Fahrenheit.] 



23 





Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dee. 


Term of 
record. 


Saguache 


18.3 
13.5 
10.1 
22.1 
18.1 
19.5 
18.2 


23.6 
21.7 
20.8 
22.3 
26.2 
24.2 
22.8 


33.6 
31.2 
32.3 
34.8 
35.5 
33.3 
33.5 


43.4 
41.6 
41.6 
45.0 
41.8 
42. 3 
41.3 


51.6 
49.2 
51.8 
52.3 
49.4 
50.5 
52.0 


63.8 
57.8 
59.1 
60.8 
58.0 
58.6 
62.0 


64.4 
61.3 
63.5 
64.2 

62.5 
63.1 
66.2 


62.7 
60. 6 
62.5 
63.7 
62.6 
62.4 
63.7 


55.7 
53.6 
55.2 
58.5 
58.8 
55.8 
55.2 


45.4 
41.4 
43.8 
47.6 
45.3 
45.3 
44.1 


33.0 
30.0 
29.7 
35.2 
36.2 
34.0 
30.0 


20. 

13.4 

17.9 

25.0 

18.6 

22.5 

21.2 


1886-1905 
1S97-1905 


Monte Vista 


1886-1896 
1892-1897 




1904-1905 


San Luis 

Fort Garland 


1891-1905 
1852-1883 


Average . . . 


18.0 


22.9 


33.2 


42.1 


51.3 


60.8 


64.3 


62.8 


55.5 


44.6 


31.6 


20. 




Wagon Wheel 


12.9 


17.6 


26.8 


35.4 


42. 2 


50.4 


54. 5 


54.7 


47.9 


38.3 


27.1 


12.7 


1898-1905 







The extremes of temperature for summer and winter at Saguache, 
Garnett, and San Luis are included in the next table. The lowest 
figure recorded is 40° below zero at Garnett in December and the 
highest figure is 98° at San Luis in August. The observations at 
Garnett are the most typical of the valley, as the station lies in the 
full sweep of the valley winds, while Saguache and San Luis are pro- 
tected by the adjacent foothills. The monthly mean temperatures 
for the winter months at Garnett range from 1° to 10° lower 
than at Saguache and San Luis, and the range of the extremes is still 
greater. 

Maximum and minimum temperatures at Saguache, Garnett, and San Luis. 
[Degrees Fahrenheit.] 



Month. 


Average. 


Highest. 


Lowest. 


Saguache: 


21 
18 
23 
60 
65 
63 

13 
13 
22 

5S 
61 
61 

22 
20 
24 
59 
64 
63 


63 
59 
64 
92 
97 
94 

55 
52 
64 
89 
88 
92 

58 
57 
63 
96 
95 
98 


-26 




-23 




— 13 




28 


July 


31 




35 


Garnett: 


-40 




-30 




-33 


June 


20 


July 


29 




30 


San Luis: 


-30 




-30 


February 


-34 




23 


July 


30 




32 







The next table gives the average monthly precipitation at various 
points in the valley calculated from all available records. The figures 
for the precipitation at Fort Garland and Wagon Wheel Gap are 
added for the sake of comparison, though they have been excluded 
in making up the average for the valley, the former for reasons given 
later and the latter because the station is not within the valley proper. 
From the valley average it will be seen that July has the greatest 
precipitation, with occasional showers in August and September. 



24 THE SAN LUIS VALLEY, COLORADO. 

Average monthly precipitation at stations in San Luis Valley. 
[Inches.] 





Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Term of 
record. 


Saguache 

Garnett 


0.26 
.08 
.24 
.11 

.78 
.49 


0.35 
.24 
.51 
.91 

.67 
.64 


0.21 
.23 
.32 
.13 

.20 
.89 


0.62 
.25 
.85 
.15 
.00 
.95 


0.89 
.72 
.81 

1.00 
.06 

1.23 


1.10 
.59 
.29 
.22 

1.00 
.67 


1.80 
1.23 
1.58 
1.13 
.94 
2.26 


1.80 
1.35 
1.28 
1.04 
1.46 
1.27 


0.86 

.84 

.87 

.64 

3.53 

1.18 


0.70 
.40 
.48 
.69 
.99 
.92 


0.28 
.25 
.22 
.30 
.00 
.36 


0.23 
.25 
.32 
.03 
.47 
.79 


1886-1905 
1891 1905 


Monte Vista 


1886-1896 
1892 1896 




1904 1905 


San Luis 


1891-1905 


Average for 
valley. .. 


.29 


.48 


.42 


.62 


.91 


.65 


1.66 


1.19 


.97 


.66 


.28 


.40 




Fort Garland 

Wagon Wheel 


.18 

.45 


.82 
.64 


.40 
.90 


.72 
.99 


.90 

1.03 


.72 
.59 


1.93 
1.53 


1.78 
2.19 


1.31 

1.42 


.54 
1.09 


1.10 

.68 


.87 
.41 


1852-1874 
1898-1905 







The next table gives the yearly precipitation for each point in the 
valley and the average for the valley itself for 1887-1905, inclusive, 
so far as there are records, except for Fort Garland. The record of 
Wagon Wheel Gap is added, as of interest from its position in the 
upper drainage basin of the Rio Grande. The mean annual precipi- 
tation for the valley is 8.33 inches. The maximum annual precipita- 
tion is 18.85 inches, recorded at San Luis in 1891, and the minimum 
is 2.88 inches, given for Saguache in 1896. San Luis and Wagon 
Wheel Gap have the highest average annual precipitation, as is to be 
expected from their geographic position. The precipitation on the 
mountains about the valley, and especially high up in the Sangre de 
Cristo and Culebra ranges east of the valley, is doubtless much greater 
than in the valley, owing to the fact that the southwest moisture- 
laden winds are forced to ascend to colder altitudes in crossing over 
those ranges, with local precipitation as a result. 

Average annual precipitation at stations in San Luis Valley. 
[Inches.] 





1887. 


1888. 


1889. 


1890. 


1891. 


1892. 


1893. 


1894. 


1895. 


1896. 




10.09 


4.41 


7.05 






! 




14.01 

10.37 

9.12 

9.44 


2.88 








4.87 

7.47 


4.46 
6.84 
7.15 


6.33 
6.22 
6.75 


3.50 




8.48 


6.21 


5.01 


6.48 


9.17 


































18.85 


11.04 


10.87 


10.58 


15.76 


12.31 














Average for \ alley 


9.59 


5.31 


6.03 


6.48 


14.01 


7.75 


7.33 


7.47 


11.74 


6.23 





1897. 


1898. 


1899. 


1900. 


1901. 


1902. 


1903. 


1904. 


1905. 


Aver- 
age. 




8.84 
.6.25 


8.06 
4.60 


5.96 
6.96 


6.25 


6.86 


7.09 
8.18 


6.51 
5.18 


7.26 
9.51 


3.76 
7.08 


7.12 




6.44 








7.22 




















7.78 




1 








.:::::.: 


9.86 
9.56 


10.14 


9.86 




13.93 


14.20 


10.04 


10.16 


13.02 


7.45 


6.98 


12.71 






Average for valley 


9.67 


8.95 


7.65 


8.21 


9.94 


7.57 


6.22 


9.05 


7.00 


8.22 






12.26 


12.25 


7.83 


9.73 


10.28 




14.50 




12.81 









GEOGRAPHY. 



25 



As explained with regard to the table of average monthly tempera- 
tures, the table of precipitation that follows combines the observations 
at Fort Massachusetts and Fort Garland. The figures for 1870-1872, 
inclusive, are regarded by the United States Weather Bureau as very 
questionable, and they have accordingly been excluded in making the 
averages. Aside from these years the table appears to be fairly 
reliable, and is of much interest for purposes of comparison. 

Precipitation at Fort Garland, 1852-1863 and 1866-1874- 
[Inches. Blanks indicate incomplete records.] 



Year. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Annual. 






















1.84 


6.34 


1.45 


9.63 


1853 


0.22 


0.76 


0.94 


6.39 


1.49 

3.93 
.98 
.00 
.75 

1.00 
.32 
.00 

1.01 
.24 
.22 


1.11 
.24 
.86 
.55 
.95 
.58 

1.32 
.72 

1.07 
.41 

1.07 


3.04 
2.14 
2.60 
2.19 

.72 
1.36 
2.72 
2.61 

.74 
1.26 

.07 


1.48 
2.61 

3.30 
3.98 


1.25 
1.53 
3.33 
1.55 
1.34 


10.68 


1854 . 


.35 
.00 
.95 
1.19 
1.22 
.55 
.25 
.13 
.00 
.13 
.35 
.02 
.42 
.16 
1.30 
1.40 
.10 
.50 
1. 23 


5.27 
.79 

2.03 
.68 
.20 
.24 
.06 
.22 
.21 
.08 


2.30 
.38 
.55 
.67 
.15 
.20 
.04 
.01 
.14 
.24 
.13 


13.10 


1855 


.00 
.15 
.80 
.54 
.00 
.20 
.03 
.24 


.67 
2.14 
.52 
.20 
.15 
.08 
.04 
.02 
.84 


1.47 
.35 
.20 
.08 
.27 
.53 
.87 
.16 
.06 


.41 
1.35 
1.51 
2.11 
.19 
.33 
.25 
.40 
.00 


15.97 


1856 


13.87 


1857 


14.66 


1858 


7.92 


1859 


4.75 
.77 
.30 

1.46 
.02 


.68 
.85 
.93 

1.78 
.03 
.79 
.26 

1.80 

2.55 
.90 

2.90 
.83 
.18 

2.05 


11.35 


1860 


6.62 


1861 


5.44 


1862 


6.33 


1863 


2.89 


1866 




1.35 


1867 


.06 
.16 
.65 
.65 
1.20 
2.25 
.00 
.50 


.15 

.90 
1.05 
1.45 
2.75 
2.25 
2.80 


.12 
.12 
.28 
.85 
2.80 
3.65 
.00 
.50 


.89 


.21 


.01 
.01 

.77 
6.65 

.25 
7.75 
1.58 

.20 


.36 
7.19 
1.28 
7.30 
1.00 
10.30 

.80 
1.72 


.29 
3.26 
1.03 
7.50 
1.25 
5.68 

.48 
1.12 


2.37 


1868 


.03 
.14 
.15 
7.10 
.00 
.01 
.25 


4.01 
3.00 
3.35 
1.75 

.00 
.20 
.50 


17.00 


1869 


.36 
7.57 
2.45 
2.78 
1.75 

.15 


2.30 
.60 
1.45 
6.25 
.00 
.08 


13.42 


1870a 


37.87 


1871" 


25.00 


1872a 


42.34 


1873 


7.75 


1874 


11.10 






Average 


.18 


.82 


.40 


.72 


.90 


.72 


1.93 


1.78 


1.31 


.54 


1.10 


.87 


Ml. 27 



a Record unreliable. 

b Average annual precipitation excluding 1870-1872, inclusive. 

AGRICULTURE. 



ORDER OF SETTLEMENT. 

The first population of the San Luis Valley was Mexican, and the 
little Mexican "plazas " are scattered along both sides of the valley but 
are more numerous in its southern part. The Mexicans constructed 
no large- irrigation ditches, and their settlements were perforce limited 
to the mountain valleys, to the border of the San Luis Valley, and to 
the immediate banks of the perennial streams in the valley. 

Following the advent of Americans came colonization schemes and 
the construction of larger canals, permitting the central part of the 
valley to be settled. North of the Rio Grande the country adjacent 
to the railway, irrigated by the Farmers' Union, Prairie Ditch, and 
San Luis canals, was first settled in preference to the more gravelly 
soil to the west. Gradually, however, the gravelly land was found to 
be fertile and suited to cultivation as well as the other, and the culti- 
vated territory spread farther westward. Then, from a combination 
of causes, the land that lay to the east along the railway and was the 
first to be cultivated was practically abandoned. These causes were 



26 THE SAN LUIS VALLEY, COLOEADO. 

(1) exhaustion of the soil by continuous cropping without rotation; 

(2) exhaustion of the water in the canals by farms nearer the heads 
of the canals; (3) failure of the canals in years of drought through 
lateness of their priorities ; (4) injurious accumulation of alkali in the 
soil. This accumulation of alkali is due to the prevailing practice of 
subirrigation. The alkali is largely of local origin, a result of the 
concentration at the surface of the salts in the soil of the affected 
region itself, but is also partly derived from the soil of the contiguous 
and higher regions to the west and carried by seepage water to the 
lower land, there coining to the surface and being precipitated. 

Remnants of the population brought in by colonization schemes 
exist in different parts of the valley, as, for instance, settlements of 
French Canadians about Carnero, of Scandinavians at Swede Corners 
south of Saguache and in the neighborhood of Swede Schoolhouse 
southwest of Alamosa, and of Mormons at Manassa, Sanford, Rich- 
field, Freedom, and, until recently, at Zapato. 

NATIVE VEGETATION. 

The native vegetation of the valley varies with the region and the 
ecologic conditions. On the high mountain sides pine, aspen, and 
spruce, lower down pinon and cedar, and in the valleys and along 
streams cottonwood and willow constitute the forest growth. The 
valley bottom away from streams is covered with a growth of "chico" 
and "greasewood," the former predominating in adobe soils and both 
growing in the loams. Sagebrush does not grow in the valley bottom 
but is found in the foothills in places. Wild currants and raspberries 
thrive abundantly, growing well up the mountain slopes. Of the cur- 
rants three varieties are found, black, red, and yellow. 

Much native hay is grown along the bottoms of the streams that 
come down into the valley from either side. These vegas, or native 
meadows, were among the first tracts taken up as homesteads, and 
on account of their value and the ease of cropping are not plowed 
up to be planted in other crops unless they run out. The market for 
hay is largely local, yet some is shipped. 

CULTIVATED CROPS. 

The principal crops are wheat, oats, wild hay, alfalfa, potatoes, peas, 
and barley. Wheat was the first crop and is the most important 
crop to-day. Very little trouble was taken in planting wheat by the 
early settlers. The brush was uprooted by dragging a heavy railroad 
rail across the land, raked up into windrows and burned, and the 
wheat drilled in directly without plowing. Such methods sufficed 
to get large yields and led to the planting of large acreage and the 
building of mills and elevators at Del Norte, Monte Vista, Hooper, 



GEOGRAPHY. 27 

Mosca, Alamosa, La Jara, and Conejos. In time the heavy wheat 
returns failed and crops were rotated, or the fields were planted in 
alternate years, lying fallow in the intervals. 

In the last few years, however, a new industry has sprung up, which 
yields good returns and which, in the long run, will be more valuable, 
in that it will restore the land to its pristine fertility. This is the 
business of fattening young lambs for the spring markets. Quarter 
sections are grown with peas, or a mixture of peas and oats, and the 
lambs are pastured on these, thus at one stroke doing away with the 
need of harvesting the crop and hauling it to market, besides resting 
the land by raising a leguminaceous crop and returning nearly all the 
mineral plant food to the soil. The practice promises to spread 
rapidly and will unquestionably make for the good of the valley. 
The meat of lambs fed on peas is said to be much improved in flavor 
and at all times commands the best prices. 

The late and short growing season in the valley of necessity cuts 
out some fruits and crops. Early corn will in a favorable year make 
small roasting ears. Apples and pears have been grown in protected 
places, but these are unimportant and fruit is mostly imported from 
the outside. 

METHODS OF IRRIGATION. 

In the San Luis Valley the method of irrigation practiced almost 
universally is a modification of subsurface irrigation, locally known 
as "subirrigation." In subsurface irrigation the water is carried in 
underground tile or perforated pipe directly beneath the roots of the 
plant to be irrigated, as, for instance, beneath a row of fruit trees. 
In subirrigation, as practiced in the valley, the water is conducted onto 
the field in trenches at such distances apart as experience and the 
character of the soil shall determine. These trenches are closed at 
the lower ends and water is supplied to them only so fast as it is taken 
up by the sides and bottom of the trenches, care being taken to pre- 
vent overflowing. The loamy character of the soil allows it to absorb 
the water rapidly, while the level character of the surface permits the 
raising of the level of ground water to a height within reach of the 
rootlets of the growing crops. The object in view is to keep the level 
of the underground water at this height. If the spring rains have not 
left the water level near the surface, it may be brought so by a pre- 
liminary flooding. 

This method requires much less care and trouble than the method 
of flooding or surface irrigation, and is as efficacious as that method, 
though it requires much more water. Its long-continued practice, 
however, brings a result that is detrimental ; that is to say, it renders the 
soil alkaline. In countries of greater rainfall, where irrigation is not 
needed, the constant flooding of the soil since its formation as a result 



28 THE SAN LUIS VALLEY, COLORADO. 

of heavy rains and the consequent run-off has leached from it much 
if not all of its content of injurious salts, as well as much of the mineral 
matter needed as plant food. For the same reason, in the so-called 
arid regions, correlated with the liability to become alkaline under 
careless irrigation is the greater fertility of the land due to the greater 
abundance of mineral plant food. 

The salts which render soil alkaline are, in the order of their inju- 
rious effects, sodium carbonate (" black alkali"), sodium sulphate 
("Glauber's salt"), and sodium chloride (common salt). These are 
originally so widely scattered in small particles through the soil and 
subsoil as not to be injurious. They are very readily dissolved in the 
water put on in subirrigation, which penetrates both the soil and the 
subsoil. As this water is drawn to the surface and evaporated, it 
leaves these salts behind it on the surface of the ground. As a result 
of this continuous process, the salts are leached from the soil and sub- 
soil and accumulate on the surface of the soil, rendering it in time 
unfit for tilling. Once in solution, the only way the salts are rede- 
posited in the soil is by evaporation. The remedy is of course to 
reverse the process of irrigation ; that is to say, to apply the water at 
the surface, preferably by flooding, and to withdraw it from below 
by drainage, thus continually carrying away the salts in solution and 
lessening their amount in the soil. This method, as just pointed out, 
has the disadvantage of removing from the soil some of its valuable 
elements. 

Not all of the water comes immediately to the surface to be evap- 
orated, especially on the less gently sloping gravelly land of the allu- 
vial-fan formations to the west. A portion of the water continues 
down the slope as underflowing ground water until forced to the sur- 
face by clay beds beneath. Here it issues as a "seep," usually making 
an "alkali spot." 

The alkali map accompanying the report on the soil survey of the 
San Luis Valley," to which the reader is referred for further details, 
shows that in the region surveyed the most alkaline territory lies in a 
semicircle about the foot of the steeper part of the great Rio Grande 
alluvial fan. The author of the report says that "the subformation 
is such that the ground water is naturally near the surface in this 
territory." In other words, this is the region where the superficial 
gravelly and sandy covering of the fan thins out and the clay beds of 
the Alamosa formation approach the surface. 

How short-sighted was the man who congratulated himself because 
his land required no irrigation when his next neighbor's land above 
was thoroughly saturated or "subbed." He simply was slowly 
accumulating a large part of his neighbor's alkali. Perhaps his 

a U. S. Dept. Agr., Field operations of the Bureau of Soils, 1903, pp. 1099-1119. 



GEOLOGY. 29 

neighbor in turn was having alkali unloaded upon his land. But the 
man for whom there is no escaping the alkali under the system of 
subirrigation is the one on whose place the seep rises to the surface. 
As noted before, the remedy lies in surface application of the water, 
with subsurface drainage, not only greatly lessening the needful 
amount and making the supply irrigate a larger territory, but carry- 
ing away the alkali. 

The report referred to above, based on careful study of the valley, 
concludes that the amount of alkali in the valley is nowhere so great 
as to preclude successful reclamation by proper methods. 

GEOLOGY. 

INTRODUCTORY STATEMENT. 

Popularly the San Luis Valley or park is supposed to be the south- 
ernmost one of a chain of four great parks, of which North, Middle, 
and South parks are the others ; in reality, it differs genetically and 
geologically from that series, which, with its southern continuation, 
Wet Mountain Valley and Huerfano Park, occupies a depression be- 
tween the Front Range and Wet Mountain axis and the Mosquito 
Range and Sangre de Cristo axis, whereas the San Luis Valley occupies 
a depression west of the latter axis and between it and the Sawatch 
Mountains. Furthermore, the former depression began to take shape 
much earlier — as far back as the Triassic at least — and has been sub- 
ject to sedimentation more or less continuously from that time until 
the Pleistocene, whereas the San Luis Valley shows no formations older 
than Miocene, and is for the most part occupied by Tertiary or early 
Quaternary sediments. 

For purposes of geologic description the valley and its environment 
divides itself naturally into four parts — the west ranges, the east 
ranges, the San Luis Hills, and the valley proper. 

THE WEST RANGES. 

The western mountains, the Sawatch and Conejos ranges, are made 
up, on their eastern flanks adjacent to the San Luis Valley, of alter- 
nations of gravel beds, andesitic flows, and rhyolitic tuffs cut through 
in places by dikes and the volcanic necks of centers of effusion. 
These flows incline toward the valley with dips varying from 6° to 15°, 
and extend under it, being penetrated in some of the wells at the south 
end of the valley. In Plate III, A, the lava-capped mesa that 
stretches eastward from Los Mogotes Peak and is cut through by the 
canyon of Conejos River is seen gradually to approach and merge 
with the floor of the valley. 



30 THE SAN LUIS VALLEY, COLORADO. 

ALAMOSA CREEK VALLEY. 

Alamosa Creek leaves the foothills about 6 miles west of Capulin, 
through a defile in the lava rim. The south side of the defile rises 
into a bluff a hundred feet high, which is shown in Plate III, B. 
This bluff, capped with pyroxenite-andesite a 40 feet in maximum 
thickness, dips 8° to 10° E. The lower part is massive and lies upon 
a water-sorted conglomerate, at the contact with which the lava 
is much broken. Bowlders from the conglomerate seem to be drawn 
up into the lava, and it is penetrated by crevices and "chimneys" 
of loose-textured rock, apparently the result of steam escaping when 
the flow covered the conglomerate. The conglomerate has a burnt, 
reddish color, and the sandy matrix is more or less consolidated and 
indurated. These gravel beds rise upstream and 300 yards west 
come to the top of the bluff, where they are interbedded with and 
underlain by brecciated pumice or rhyolitic tuffs. Farther west these 
in their turn are underlain by other gravel beds, which become more 
arkose toward the bottom, where they rest on pinkish mica andesite. 
In each of the conglomerate beds, mingled with the waterworn 
bowlders, there are numerous subangular bowlders, some of which 
are rudely facetted and in outline strongly resemble glaciated 
bowlders. Though none was seen which exhibited striae or glacial 
scratches, yet the field observations left the writer convinced that a 
period of local glaciation antedated the last lava flow in this vicinity. 
If this glaciation occurred in the headwaters of Alamosa Creek, 
the carrying of the bowlders by the stream to their present site would 
have worn away the superficial glacial striae and left them in the 
condition in which they are now found. 

The ledge of pink mica andesite varies from about 30 to more than 
70 feet in thickness and is the most persistent and characteristic bed 
of the eastern border of the west ranges. It furnishes the stone which 
has been most widely used for building purposes in the valley. It 
can be quarried in blocks of any desired size, works easily when 
freshly quarried, hardens on exposure, and has in general a pleasing 
creamy tint, though varying somewhat in shade in different outcrops. 
Many public buildings, as well as business blocks and residences, in 
Antonito, Conejos, La Jara, Manassa, Alamosa, and Monte Vista 
are constructed of this stone. 

Below the pink mica andesite are successive beds of andesite and 
rhyolitic tuffs and vitrophyres. The following is a section of the 
various beds from the uppermost sheet of pyroxenite-andesite down- 
ward to the pink mica andesite: 

a The various igneous rocks noted herein have been determined by Whitman Cross, of the United States 
Geological Survey. 



GEOLOGY. 31 

Section of south side of Alamosa Creek canyon, near the lower end. 

Feet. 

Pyroxene andesite; irregular contact at base 40 

Bowlders in sand matrix 12 

Bedded sand 1 

Bowlders in sand matrix 12 

Bowlders in brecciated pumice tuff 3 

Bowlders with indurated sand matrix 1 

Bowlders and sand; Irregular contact at base 2 

Pumice breccia with small waterworn pebbles 2 

Sand and bowlders of various shapes — angular, subangular, and 

waterworn 4 

Pumice breccia 14 

Concealed, probably gravel 8 

Brecciated pumice with rounded quartz and felsite pebbles |- inch 

in diameter. Upper portion conglomeratic with bowlders of 

various rocks 12 

Pumice 8 

Apparently pumice 80-100 

Bedded gravel and sand becoming lighter in color and arkose 

toward the bottom 50 

Pinkish mica andesite. 40± 

CAT CREEK VALLEY. 

The canyon of Cat Creek at the point where it debouches upon the 
plain is not deep. At the quarry, about a mile up the canyon, the 
mica andesite first appears, continuing to the forks of the canyon at 
Tiptons, forming the walls of the south canyon to a point 3 miles 
beyond, and showing in the walls of the north canyon to the vicinity 
of Wood's cabin, where the road leaves the canyon and goes up the 
steep hill. From this it will be seen that the eastward dip of the 
mica andesite here does not exceed the drainage gradient of Cat 
Creek, which is a considerably lower dip than the same rock shows in 
Alamosa Creek. 

ROCK CREEK VALLEY. 

In Plate IV, A, is shown Painted Rock Bluff along the north bank 
of Piedra Pintada (Painted Rock) Creek, locally called Rock Creek, 
which takes its name from the fact that for about a quarter of a mile 
in the middle of the bluff shown in the photograph the face of the 
soft andesite bluff is covered with Indian picture writing. The andes- 
ite ledge rises westward for a mile and a half to the forks of Rock 
Creek, where it shows a face of 60 or 80 feet of the pinkish mica 
andesite, the thickest exposure noted. 

These beds of pinkish mica andesite, which appear in the canyons 
of Alamosa Creek, Cat Creek, and Rock Creek and elsewhere on the 
west side of the valley, seem to be parts of the same flow or at least 
to belong to closely related flows in all three canyons. The bed may 
actually be continuous through the hill from one canyon to the other, 



32 THE SAN LUIS VALLEY, COLORADO. 

but this is not evident. The high points between the canyons, such 
as Chiquita Peak, seem to be local extravasations through the andes- 
itic sheet. 

WEST OF MONTE VISTA. 

In the foothills 6 miles west of Monte Vista the flows, dipping 
eastward more steeply than the slope of the hills, form "hogbacks." 
Several miles farther west, at the limekiln, a normal fault, bearing 
N. 30° W., with a throw of 50 or 60 feet to the west, has been pros- 
pected through a distance of three-fourths of a mile. Throughout 
this extent the brecciated fault zone is filled with a vein deposit of 
calcareous onyx, which has been burned for lime but has not yielded 
any blocks of onyx marble of commercial size. The width from wall 
to wall varies from 20 to 40 feet, though at the widest places a portion 
of the space is taken up by slabs of the country rock, which seem to 
be either mica andesite or mica rhyolite. 

A darker, heavier flow, later than the mica andesite and probably 
corresponding to the upper flow at the foot of Alamosa Creek canyon, 
outcrops in a few places, notably near the railway cut midway between 
Monte Vista and Del Norte, and also in the isolated hill La Loma del 
Norte, across the Rio Grande, 2 miles east of the last-mentioned 
exposure. 

VICINITY OF SAGUACHE. 

The eastern edge of the La Garita Hills from Del Norte to Saguache 
was not examined, but what appears from a distance to be the pink 
mica andesite occurs in great massive bluffs and makes up a large part 
of the hills. In the vicinity of Saguache there are a number of small 
hills of basic lava, the result of local extravasation. The hill near 
the cemetery southeast of the town is made up of olivine diabase and 
hornblende andesite. To the northeast, in the vicinity of Hunt 
Springs, similar hills appear; also farther northeastward to the vicinity 
of Villa Grove. North and south of that locality, skirting the edges 
of the foothills, are heavy outcrops of Carboniferous rocks dipping 
50° E. 

AGE OF THE ROCKS INVOLVED IN THE WEST RANGES. 

In the discussion of the mesa northwest of San Luis village, the 
northwest prolongation of the San Pedro Mesa, its equivalence in age 
with the basic lava capping the lava conglomerate series making up 
the western ranges is suggested (p. 39). There also is noted the 
correlation of the San Pedro Mesa and its extension with the lava- 
capped mesa near Fort Garland, which Hayden, following the forma- 
tion up the Rio. Grande from its type locality, identified as the 
Santa Fe formation, later shown by Cope to be of Miocene age. This 
will be assumed, then, to be the age of the alternating series of andesite 
flows and conglomerates of the eastern border of the western hills. 






GEOLOGY. 33 

Indeed, Hayden a noted the occurrence of the Santa Fe formation at 
the base of the western mountains south of Saguache Creek. The 
similarity of constitution on the opposite sides of the valley supports 
the tentative correlation. 

GLACIATION OF THE WEST RANGES. 

While evidence of glaciation in the upper courses of Conejos River 
and La Jara, Alamosa, Cat, and Rock creeks is plain, the lower limit 
reached by the ice in each course is difficult to determine. Distinct 
terminal moraines are not present, but instead the unquestioned drift 
of the upper courses becomes thinner and less characteristic in the 
lower courses and may be succeeded by one or two sets of terraces. 

The Alamosa Creek glacier manifestly occupied the U-shaped valley 
of that creek down nearly to the "box canyon," spreading across the 
flat west of Chiquita Peak into the valley of Cat Creek and coalescing 
with the ice in that valley. Below the "box canyon" there are two 
terraces, both developed on the south side of the valley. The lower 
one, apparently alluvial, is 60 feet high and 100 to 150 yards wide. 
The upper one, 30 feet higher, is covered with bowlders, in part 
glacial, and has an irregular surface apparently morainic in origin — 
an appearance that is borne out by the arrangement of material so 
far as that can be seen. A mile farther down the creek a third terrace 
sets in 35 feet high above the valley bottom. Upon the surface of 
this terrace are two and in places three trains of bowlders, roughly 
parallel, steeper toward the creek and sloping toward the valley wall. 
They appear to be morainic in origin, though the occurrence of the 
alluvial terrace higher up the creek seems to cast doubt upon such 
interpretation. 

In Cat Creek valley the disposition and character of the drift that 
lies upon the andesite at the quarry near the lower end of the canyon, 
as well as of that on the sides of the canyon all the way up, seem to 
point to their deposition directly by the ice. The two forks of the 
creek occupy trenches cut in the eastward extension of the glaciated 
flat west of Chiquita Peak. No terminal moraine is apparent. 

The headwaters of Rock Creek rise in the rolling glaciated amphi- 
theater shown in Plate II, B. In the vicinity of the forks of the creek 
there is much evidence of glaciation. Parallel to Painted Rock 
Bluff, but on the south side of Rock Creek, there is a long terrace, steep 
in front, the gravel-covered surface sloping gently away from the 
creek. This terrace is in all respects like the uppermost terrace of 
Alamosa Creek and apparently is lateral morainic in character. 

No further evidences of glaciation were noted on the west side of 
the valley. There are no indications about Del Norte that the Rio 

a First, Second, and Third Ann. Repts. U. S. Geol. and Geog. Survey Terr., p. 17G, 
42120°— wsp 240—10 3 



34 THE SAN LUIS VALLEY, COLOKADO. 

Grande glacier reached that point, and at Saguache there are no signs 
of glaciation. Though farther west these stream valleys must have 
held Pleistocene glaciers, the conditions were such that they did not 
extend as near to the San Luis Valley in this locality as did those 
farther south. 

THE EAST RANGES. 

STRATIGRAPHY AND STRUCTURE. 

Commencing north of Poncha Pass, the Sangre de Cristo Range 
forms a true sierra extending southeastward and culminating in the 
massif of the Sierra Blanca group of peaks. The sky line, formed by 
a series of pointed peaks with intervals of sharply serrate and jagged 
crest line, and the precipitous front, rising abruptly from the level 
plain to the height of a mile, combine to make this range one of the 
boldest and most majestic in the country. 

The geologic boundaries in this range, as laid down on the Hay den 
map, are very much at fault. Only the most cursory examination 
has been made of the range, which has been ascended or crossed by 
geologists but a few times at most. The formations involved, so far 
as known, are basal gneiss, schists, and granite; intrusive granite; 
quartz conglomerate; pudding-stone conglomerate and red sandstone; 
and limestones and shales. The ages assigned to these formations 
by the Hayden geologists are as follows: Gneisses, schists, etc., 
Archean; pudding-stone conglomerate and red sandstone, upper Car- 
boniferous; and limestone and shales, lower Carboniferous. 

Reference has been made to the occurrence of limestones and sand- 
stones in the vicinity of Villa Grove. The outcrops, as laid down on 
the Hayden map, show lower Carboniferous rocks facing the valley 
and upper Carboniferous behind and above. The dip is toward the 
valley, thus indicating an overturn. On the east side of the valley 
the same distribution of formations is represented, the upper Carbon- 
iferous forming the upper flanks of the Sangre de Cristo Range, the 
lower Carboniferous restricted to two outcrops on the western foot 
of the range. This stratigraphic arrangement, taken in connection 
with the described anticlinal structure of the range, is altogether 
improbable. Lee has recently shown a for the Culebra Range that 
the limestones marked on the Hayden map as lower Carboniferous are 
in reality upper Carboniferous and lie on the basal Archean granite, 
indicating the entire absence of lower Carboniferous; and this is prob- 
ably true for the whole range except the north end near Salida, where 
lower Carboniferous limestone carrying fossils with a strong Devonian 
facies is known. If the same mistake that was made in the Culebra 
has been made in regard to the age of the limestone east and west of 
Villa Grove, the structural difficulty disappears and the range is 
readily interpreted as a great anticline and the valley as a great 

a Jour. Geology, vol. 10, 1902, pp. 393-396. 




£ a, 



GEOLOGY. 35 

syncline, the limestone being younger and overlying the sandstones 
and conglomerates. That the structure of the range is not a simple 
anticline, however, is well shown by a section up the canyon of Willow 
Creek, which leaves the mountains 2 miles southeast of Crestone. A 
view looking up the valley from Willow Creek Park is shown in Plate 
V. The prominent ledge just beyond the middle of the picture dips 
south of west 70° to 80° and consists of conglomerate. This is the 
formation which was called "Arkansas sandstone" by Endlich and 
which has here been spoken of as pudding-stone conglomerate because 
many of the bowlders in the conglomerate are themselves conglom- 
eratic. Some of the bowlders are immense, Emmons a noting some 
25 to 50 feet in diameter. The pebbles and bowlders are of crystal- 
line rocks of various kinds and colors. Up the valley the dip ap- 
proaches the vertical, then is inclined the other way, getting lower, 
and at the head of the valley the structure develops into the pos- 
sibly faulted syncline shown in Plate VI, reproduced from a photo- 
graph taken near and looking toward the crest of the range. The 
creek from its source to the lower lake, a distance of 3 or 4 miles, 
flows approximately along the axis of the syncline. There is proba- 
bly a closely appressed anticline between Willow Creek Park and the 
syncline just mentioned. The conglomerate extends all the way 
from the upper end of the park to the crest of the mountain. The 
texture seems to grow finer upward, becoming practically that of a 
coarse reddish sandstone at the axis of the syncline, but about the 
head of the creek the rock is coarsely conglomeratic again. Making 
allowance for the appressed anticline, the thickness of the conglom- 
erate, as can be seen, is enormous, so that the question of the source 
and origin of the conglomeratic material may well be difficult, as 
Emmons found it. 6 

The axis of the range is in general made up of intrusive granite 
flanked on either side by conglomerate, though the conglomerate 
extends across the crest of the mountains near Electric Peak and the 
head of Willow Creek. Beginning north of Crestone, a band of the 
older granite sets in, widening toward the south until, with the back- 
bone of later intrusive granite, it takes in the whole range, the sedi- 
mentary rocks south of Music Pass being restricted to the east foot 
of the range. 

In the saddle between Baldy and Blanca peaks is a bed of con- 
glomerate which is quite different from the conglomerate in the north 
end of the range, in that the pebbles, which rarely exceed 1 or 2 
inches in diameter, are all of pure quartz, while the bowlders of the 
Carboniferous conglomerate are large and are made up of all sorts of 
igneous rocks. This conglomerate in the gap has a thickness of a 
hundred feet or so, rests on the granite, and has a very ferruginous 

a Bull. Geol. Soc. America, vol. 1, p. 262. &Op. cit., p. 265. 



36 THE SAN LUIS VALLEY, COLORADO. 

sandy matrix, the reddish color showing at a long distance. Down 
Ute Creek the conglomerate is more pronounced in character, and it 
lies against the foot of Baldy Peak upon the truncated edges of 
steeply dipping and intruded crystalline rocks. Its apparent thick- 
ness is over 100 feet, and the dip is 14° to 16° N. 15° E. It stretches 
away north of Baldy Peak down the valley of Huerfano River, with 
a dip of 8° or 10° in a direction north of east. On the north side of 
the valley the dip of the contact, which from the crumpled condition 
of the conglomerate seems to be a plane of movement, is 36° in a 
direction south of east. To the east the dip is more gentle, 20° in 
the same direction. In the distance down the north side of the 
valley can be seen bare white patches of limestone or light shales. 
No doubt the upward formations succeeding the conglomerate above 
would be shown in a section down the ridge in the direction of the 
dip, and perhaps also the relation of the conglomerate to the con- 
glomerates and limestones of the northern part of the range and of 
Veta Pass. These relations not having been ascertained, the age of 
this conglomerate must remain for the present undetermined. An 
apparently similar series of rocks in the Culebra Range just east of 
San Luis has been described by P. H. and E. C. van Diest, as will be 
noted below. 

Though it is marked on the Hayden maps as Archean, both Hayden 
and Stevenson pronounced the mass of the Blanca group to be of 
intrusive rock. For the most part, and particularly in the western 
portion, it consists of coarsely crystalline granite, without plication 
or schistosity, but with a system of northeast-southwest joints and 
fissures. Gneissic and schistose rocks make their appearance along 
Ute Creek, as noted below. Also, in the lower foothills immediately 
south of Blanca Peak, the rocks are gneiss or gneissoid granite, the 
laminae striking northeast and southwest similarly to the veins and 
fissures in Blanca Peak. 

The outcrops in La Veta and Sangre de Cristo passes and to the 
west, lying as they do on the great highway into the valley, have been 
noted by Schiel, Hayden, Ruffner, Endlich, and others, and Lee has 
collected fossils from them. The beds are red sandstone, conglom- 
erates, shales, and limestones. Endlich states that where the sand- 
stones appear from beneath the eastern Cretaceous in the pass they 
stand nearly vertical but incline to the east, the dip becoming lower 
toward the central mass of intrusive rock to the west, beyond which 
the sandstones and limestones set in again, with the dip reversed, 
and soon pass under the axis of a syncline. Beyond the syncline 
the limestones are involved in a very acute anticline and the west 
fine of the anticline is faulted so that it abuts squarely against 
the basal granite. Hayden and Endlich both pronounced these 
limestones to be upper Carboniferous, and collections by Lee agree 



GEOLOGY. 37 

with this determination. A similar series, but with different oro- 
graphic features, is described by Endlich as occurring at the head of 
Indian Creek. In the ninth report of the Hayden Survey, for 1875, 
Endlich describes a section (No. VIII) of the east side of the Culebra 
Range about halfway between Culebra and Trinchera peaks. The 
lower Carboniferous limestone is represented as lying on the east 
flank of the granite backbone and overlain in turn by red upper 
Carboniferous sandstones, whose dip becomes steeper to the east until 
they disappear beneath the vertical outcrop of Dakota sandstone in 
"Stonewall" Valley. Lee° has shown by a good collection that the 
limestone is upper Carboniferous and expresses the opinion that the 
red sandstones belong to the "Red Beds." 

E. C. and P. H. van Diest 6 describe a block of quartzites and 
siliceous limestone faulted against the granite at a locality on the 
Rito Seco, about 9 miles northeastward from San Luis. The lowest 
member is a thin bed of conglomerate, composed of light bluish and 
greenish pebbles of quartz cemented by oxides of iron and manganese. 
Above this come 160 feet of white saccharoidal quartzites overlain by 
a thin bed of shale and 200 feet of light-gray siliceous limestones, and 
those in turn are topped by darker limestones. The fault which 
throws them against the granite on the east bears N. 35° E. and dips 
52 \ ° NW. The formations themselves dip 5° or 6° E., into the 
mountains. No fossils were found, but on the basis of lithology the 
authors assign the quartzites to the Cambrian and the limestones to 
the Silurian. 

While developed on a much smaller scale here, the conglomerates 
as described bear a striking resemblance to those on upper Ute 
Creek. It will be recalled that farther down the ridge from the 
outcrop described north of the Huerfano, and overlying it, several 
bare white spots were noted. It seems altogether probable that these 
represent a greater development of the limestones overlying the 
quartzite of the Rito Seco. 

Enough has been said to indicate that little is actually known of the 
geology of the Sangre de Cristo and Culebra ranges and that it is an 
inviting field for closer study. 

GLACIATION OF THE EAST RANGES. 

The various stream valleys heading against the crest of the Sangre 
de Cristo Range all held Pleistocene glaciers, the morainic remains of 
which fall into two systems showing the existence of two periods of 
glaciation. The moraines ordinarily reach down to about 9,500 to 
9,000 feet above sea level and crown the summits of the great alluvial 
cones that spread out from the mouths of the stream canyons. The 
moraines of both systems are comparatively fresh looking, and the 

a Jour. Geology, vol. 10, 1902, pp. 393-3%. b Proc. Colorado Sci. Soc, vol. 5, 1894, pp. 7G-80. 



38 THE SAN LUIS VALLEY, COLORADO. 

outer, older ones are not noticeably more eroded than or different 
topographically from the inner, later ones. Some of the inner 
moraines are lower, some higher than the outer ones, and though they 
are generally shorter than the older moraines, some of them, as in 
Bear Creek valley, transgress the older moraines and extend farther 
out upon the alluvial slopes, these irregularities being due presumably 
to varying local climatic conditions in Pleistocene time. 

Black Canyon, just east of Orient, has lateral moraines on either 
side of the valley, 100 to 200 feet high and reaching to the alluvial 
slope at the mouth of the canyon. A prominent moraine juts out 
from the Willow Creek canyon, east of Crestone. Behind the moraine 
is the park or meadow shown in Plate V, the bed of an extinct glacial 
lake. Two existing glacial lakes are found in the U-shaped valley 
above the park, as well as striae, roches moutonn^es, and other evi- 
dences of ice occupation. South Zapato Creek valley, heading in the 
Blanca massif, exhibits the same evidences of ice occupation, together 
with a double crescentic moraine crowning a great alluvial fan at the 
height of 1,500 feet above the level of the valley. The inner moraine 
formerly inclosed a small lake, the outlet of which cut through the 
moraine where it adjoined the canyon wall on the north side and, once 
incised in the rock, has continued to cut back a narrow winding cleft, 
through which the water pours, forming the picturesque Zapato Falls. 
Middle, Bear, Little Bear, Blanca, and Ute creeks, the circle of radiat- 
ing streams flowing down the west and south sides of Blanca Peak, 
each held a glacier which came down to and terminated upon the 
apex of its alluvial fan. At the head of Huerfano Valley, snugly 
under the northeast face of Blanca Peak, there yet remain two small 
characteristic glaciers. a 

The Culebra Range suffered glaciation to a similar extent, according 
to Willis T. Lee. 6 

SAN LUIS HILLS. 

Stretching northeastward across the valley from Antonito to Fort 
Garland is a series of basaltic hills, flat topped and higher west of the 
Rio Grande, lower and more rounded east of the river, degenerating 
into a lava-capped mesa, the north border of which forms an escarp- 
ment along the south side of Trinchera Creek. At a point 5 miles 
southwest of Fort Garland this escarpment swings south, joining the 
San Pedro Mesa at San Luis. These hills and mesas form the south- 
east limit of the artesian basin, the sand and clay beds of which abut 
against the older formation, numerous springs coming up along the 
contact, particularly in the lower course of Conejos River. This 

a For a fuller description of these glaciers and the Pleistocene glaciation generally see Jour. Geology, vol. 
15, 1907, pp. 15-22. 
6 Personal communication. 



GEOLOGY. 39 

contact in all probability marks a fault scarp, the older strata 
forming the west ranges and the floor of the valley being deeply 
downthrown to the northwest in the formation of the depression in 
which the sands and clays of the artesian system were deposited. 

THE VALLEY. 

In the San Luis Valley there may be distinguished two classes of 
more or less unconsolidated gravels, sands, and clays, an older series 
of conglomerates with intercalated lava flows, and a younger over- 
lying series of blue clays with interstratified sand beds. 

SANTA FE FORMATION. 

The older conglomeratic series makes ,up the small isolated mesas 
and the higher foothills about Fort Garland and southward along the 
western base of the Culebra Range, as well as the basalt-covered San 
Pedro Mesa and its northward continuation which has been men- 
tioned in the discussion of the San Luis Hills. Hayden a describes 
these mesas and refers them to the Santa Fe formation. A thin sec- 
tion of some of the consolidated sands from beneath the lava in the 
north end of the San Pedro Mesa near San Luis shows, microscopic- 
ally, a prominent calcareous cement. The sand itself is in part vol- 
canic debris and in part of aqueous origin. The age of the Santa Fe 
formation has been shown by Cope h from well-known and char- 
acteristic vertebrate remains to be Miocene. The mesas east and 
south of Fort Garland are capped by a flow of basalt, while sheets of 
the same rock are interbedded with the gravels and sands of which 
the mesas are composed. 

A series of deposits northwest of Fort Garland, the "compact 
drift" of Endlich, c deserves notice. A great alluvial fan that formed 
on the left fork of Ute Creek has been trenched by the creek and 
shows a succession of terraces. Northwest of Fort Garland a mesa 
approximately 150 feet high is apparently a portion of this fan, which, 
with others formed by the other streams that converge at Fort Gar- 
land, filled up the angle of the valley between the Blanca group on 
the northwest and the basalt-capped mesa southeast of Garland. 
The mesa is covered with a sheet of gravel ranging from pebbles up 
to bowlders 12 inches in diameter, and is made up of fine buff sand or 
unindurated sandstone, with here and there a gravel layer consisting 
of various kinds of crystalline rocks, the whole dipping 10° or 12° E. 
In the next mesa due west, up the draw, the dip of the soft sand- 
stone is somewhat steeper, ranging from 12° to 22° in a direction north 
of east. Some of the sandstone beds are quite indurated. No fos- 
sils are to be observed. The dip continues on across the mesa for a 

a Ann. Repts. U. S. Geog. and Geol. Survey Terr., 1867, 18G8, and 1869, p. 175. 
6 Ann. Rept. Chief of Engineers for 1874, Appendix FF, p. 127. 
cAnn. Rept. U. S. Geol. and Geog. Survey Terr., 1875, pp. 149, 222. 



40 THE SAN LUIS VALLEY, COLOEADO. 

mile, but shifts to the south. Toward the west edge of the mesa the 
high points are composed of igneous rocks projecting through the 
sands. Within 200 yards of the igneous rock the sandstone becomes 
more and more bowldery, until in the immediate neighborhood of the 
igneous rock it is composed almost exclusively of bowlders and all 
stratification is lost. The igneous rock has not been intruded into 
the sandstone, for the contact is everywhere such as would result 
from the deposition of the sandstone upon a surface that had been 
subject to subaerial weathering. Distinguishing these beds from 
Tertiary lake beds under the appellation "compact drift," Endlich 
correlated them with the valley glacial drift of the Sangre de Cristo 
Range, though believing them to belong to an early stage of the 
glaciation. Hayden referred them to the Santa Fe formation, and 
the present writer coincides in that correlation. 

Another occurrence of the older material is in the great sand dunes 
west of Mosca Pass. Endlich a regarded the dunes as of recent 
origin and derived from the drifting sands of the valley, but Hayden 6 
referred them to the Santa Fe formation. For the reasons given on 
page 48, Hayden's is regarded as the true interpretation. 

No fossil remains are known to have been found in the Santa Fe 
formation within the limits of the San Luis Valley, its age determina- 
tion depending upon localities farther south in the Rio Grande 
valley. 

ALAMOSA FORMATION. 

To the younger upper series of blue clays with interstratified 
water-bearing sand beds, which occupy the bottom of the valley 
proper, the name Alamosa formation has been given, c from the town 
of that name near the center of the valley. 

The low relief of the valley region renders natural exposures of the 
Alamosa formation very scarce, the best one being afforded by 
Hansen Bluff (PI. VII, B) on the east bank of the Rio Grande, 
nearly east of the Peter Hansen ranch house. 

Section of Alamosa formation in Hansen Bluff. 

Recent: Feet. 

Gravelly slope 4 

Conglomerate, indurated sandy clay matrix 4 

Alamosa formation: 

Fine gravel and sand, loose 3 J 

Fine-grained reddish sand 2\ 

Black and red sand -. \ 

Drab joint clay, with a great many white indurated nodules \\ 

Coarse indurated sand and small quartz pebbles 4 

a Ann. Kept. TJ. S. Geol. and Geog. Survey Terr., 1875, p. 143. 
b First, Second, and Third Ann. Repts. U. S. Geol. and Geog. Survey Terr., p. 176. 
c Siebenthal, C. E., The San Luis Valley, Colorado: Science, new series, vol. 31, No. 802 (May 31, 1910), 
pp. 744-746. 



U. S. GEOLOGICAL SURVEY 



WATER-SUPPLY PAPER 240 PLATE VII 




A. BUCHER WELL. 




\> 



&t - 







B. HANSEN BLUFF. 
Showing stratigraphy of the Alamosa formation. 



GEOLOGY. 



41 



Alamosa formation — Continued. Feet- 
Buff to light-drab sandy clay 10£ 

Fine and coarse sand in laminae 5 \ 

Olive-green sandy joint clay, with shells 2\ 

Banded drab sand, with clay pockets 1 

Fine and coarse pebbly sand in indurated laminae \\ 

Loose black sand \\ 

Fine banded clayey sand 1 \ 

Coarse sand and clay, with quartz pebbles 2\ 

Debris slope to river 12 

61i 

The following well section at Alamosa will illustrate this formation 
to a depth of 725 feet: 

Section of Alamosa formation, from record of S priesterbach well. 



Thick- 
ness. 



Depth. 



Recent: 

Soil and clay 

Coarse sand 

Alamosa formation: 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

• Lumpy black clay . . 

Clay 

Sand (first flow) 

Clay 

Sand (second flow).. 

Very hard clay 

Sand (third flow) . . . 

Hard clay 

Very soft sandy clay 

Hard clay 

Sand (fourth flow) . . 

Hard clay 

Sand (fifth flow) 

Hard clay 



Feet. 
31 
15 h 

2 

6 

6 

3 

4 

5 

11 

3 

17 

1 

23 

4 

113 

4 

249 

7 

90 
13 
20 
GO 
6 
30 
14 
13 
2 



Feet. 
3* 
19 

21 

27 

33 

36 

40 

45 

56 

59 

76 

77 

100 

104 

. 217 

221 

470 

477 

567 

580 

600 

660 

666 

696 

710 

723 

725 



It is more than likely that minor alternations of sand and clay below 
a depth of 100 feet have not been taken into account in the record 
above. The following log of a well on the ranch of Mr. D. E. New- 
comb in the SW. | sec, 22, T. 36 N., R. 10 E. ; will illustrate this point: 

Section of Alamosa formation, from record of well on D. E. NewcomVs ranch. 





Thick- 
ness. 


Depth. 


Recent: 

Soil 


Feet. 
14 

8 

30 
11 

4 
11 

1* 


Feet. 
14 


Gravel 


22 


Aiamosa formation^ 

Light clay 


52 


Coarse dark sand 


63 


Brittle clay 


67 


Blue clay 


78 




79J 



42 THE SAN LUIS VALLEY, COLORADO. 

Section of Alamosa formation, from record of well onD.E. NewcomVs ranch — Continued. 



Alamosa formation— Continued 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Blue clay 

Sand 

Clay 

Sand (strong flow) 

Hard blue clay 

Sand (flow) 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Red clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand (flow) 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Clay 

Sand 

Gravel 

Sand 



Thick- 
ness. 



Feet. 



V, 

4 

4 

1 

1 

6; 
l 

4 
14 

5 

2 

2 

11 

Si 

3 

4 

6 

2 

7 

1 

9 

5 

5 

5 
10 
12 

1 

2 

2 

7 

2 

7 

3 

9 

3 

1 

1 

1 

7 

5 

5 

3 

1 

7 

3 

5 

2 

1 

2 

2 
12 

3 

4 
14 

2 

1 

7 

5 

3 

2 

2 

3 

6 

2 

3 

5 

4 

1 
| 

2| 

9" 

3 

6 



GEOLOGY. 



43 



This well, with over eighty changes in the character of material 
penetrated in less than 400 feet, will show the impossibility of corre- 
lating the well records one with another or of constructing any 
other than an ideal section of the valley. The multiplicity of wells 
in the valley, the rapidity and monotony of changes in the formation, 
and the short time involved in sinking the average well combine to 
discourage the systematic preservation of well records. Only occa- 
sionally, when the person having the well sunk is especially interested, 
is there any record kept. Most drillers in the valley are perfectly 
acquainted with their particular field and know beforehand at what 
depth, within a narrow margin, the desired flows will be found. 
Several wells are deeper than the Spriesterbach well, but there is only 
one other deep well with an accurately kept record. The Bucher 
well at Alamosa is over 1,000 feet deep, the Denver and Rio Grande 
Railroad well at Moffat is 1,045 feet deep, and the "oil well" east of 
Mosca is 1,283 feet deep, and several others are over 1,000 feet, but 
of these there is a record only of the "oil well," which is as follows; 

Section of Alamosa formation, from log of well No. 1, Chicago and San Luis Oil Company, 
SW. i SE. I sec. 5, T. 39 N, R. 11 E. 



Recent: 

Sand and clay 

Alamosa formation: 

Blue clay 

Black sand 

Fine sand and clay 

Blue clay 

Blue clay and fine sand (water, small flow) 

Blue clay (more water, some gas) 

Fine white sand (more water, some gas) 

Hard blue clay 

Sand, with bones and shells (flow of gas) 

Clay shale 

Fine sand 

Fine green sand ■ 

Clay shale, hard, with plentiful shells (gas increasing) 

Blue clay and sand (strong water, with gas) 

Blue sand (strong water, with gas) 

Black sand (strong water, with gas) 

Hard clay (strong water, with gas) 

Hard clay, streaks of sand (strong water, with gas) . . . 

Clay shale (strong water, with gas) 

Clay and sand (strong water, with gas) 

Hard blue shale, shells and moss 

Softer blue shale 

Harder blue shale 

Blue shale 

No record 



Thick- 
ness. 


Depth. 


Feet. 


Feet. 


30 


30 


4 


34 


16 


50 


41 


91 


5 


96 


148 


244 


125 


369 


8 


377 


9 


386 


6 


392 


25 


417 


20 


437 


5 


442 


42 


484 


198 


682 


53 


735 


42 


777 


26 


803 


84 


887 


81 


968 


7 


975 


111 


1,086 


72 


1,158 


68 


1,226 


45 


1,271 


12 


1,283 



The foregoing sections display as well as possible the constitution 
of the Alamosa formation. Its contact with the underlying Santa Fe 
formation, though nowhere exposed, is readily shown to be one of 
unconformity. Some of the deeper flowing wells to the southwest 
end in what is called the gravel flow, beyond which the drilling ma- 
chines used in the valley are not able to go. Still farther south 
and west, outside of the limit of flowing wells, there are a number 



44 THE SAN LUIS VALLEY, COLORADO. 

of wells which, after passing through the series of clay and sand beds 
and a basal gravel bed, penetrate a sheet of lava, below which various 
gravel and pumice beds are found. Without question the lava and 
the beds beneath it belong to the Santa Fe formation. The wells of 
which there are records are too widely scattered to show whether the 
lava sheet has an erosional configuration or not, but near the point 
where the Rio Grande enters the San Luis Hills the Alamosa forma- 
tion abuts against the lavas of those hills at the surface and presum- 
ably against the gravel beds of the Santa Fe formation beneath the 
surface. So, too, the topography exhibited by the foothills of the 
Culebra Range, composed as they are of the Santa Fe formation, is of 
a much older type than that of the Alamosa formation. 

Though it is impossible to correlate well sections that are any great 
distance apart, or to trace any stratum of clay or sand from point to 
point, nevertheless the experience of drillers is that the "first flow" 
(and by inference, the successive lower flows) in any neighborhood 
is found at very near the same horizon or depth, gradually increasing 
in depth toward the center of the valley. For instance, the first flow 
in the region of Monte Vista is at about 100 feet, near Parma 175 feet, 
and at Alamosa about 250 feet. Between Center and Hooper the 
first blue clay is struck at about 80 feet along the entire distance. At 
Center the first flow, a very small one, is found at 155 feet, at Garnett 
the first flow is at about 175 feet, and at Hooper and Mosca at about 
200 feet. That the uppermost water-bearing bed is covered by a 
stratum of clay persisting from the center of the valley to the receiving 
area in the gravelly alluvial slope at the edge of the valley is likewise 
indicated by the fact that the water is not alkaline. If the bed came 
to the surface anywhere inside the irrigated area of the valley, it 
would necessarily absorb more or less alkali from the irrigating waters. 
Even in the Mosca-Hooper district, where the tinted deeper waters 
are highly alkaline, the uppermost flow is clear and potable. 

The cross section in figure 3, though largely ideal, is based upon 
all the data available. A fact that comes out in the construction of 
this section is that wells near the center of the basin show heavy 
clay beds and fewer aquifers; that wells nearer the margin of the 
valley, but not too close to it, show thinner clay beds and more 
aquifers; whereas wells at the limit of the flowing- well area, or out- 
side that line, show but few and thin beds of clay, with sand largely 
predominating. This is but an expression of the physical limitation 
of sedimentation. Sand, being coarser and heavier than clay, would 
be expected to constitute the bulk of the deposits near shore — that is 
to say, near the edge of the valley — while the finely divided clays 
would make up the greater volume of the formation in the center of 
the valley. Beds of sand, thinning toward the center of the valley, 
pinch out before reaching that region, and beds of clay thin out before 



GEOLOGY. 



45 



re aching the margin of the b asin . Thus 
the region where both clay and sand 
beds exist in greatest number is a band 
of indefinite width which circles the 
basin some distance inside the margin 
of the flowing- well area. These features 
are shown in the diagram (fig. 4). If it 
be argued that the lower aquifers, hav- 
ing the heaviest pressure, must be con- 
fined by clay beds which extend farther 
up the alluvial slope in the region of in- 
take, it should be remembered that the 
pressure where the wells are numerous 
is dependent largely on their number. 
The deeper the aquifers the fewer are 
the wells that reach them. Of two 
aquifers drawing from a common bed of 
sand in the marginal region, and divided 
by a clay septum only part way back 
from the wells, and hence theoretically 
with identical pressures, the lower one 
will nevertheless exhibit the higher pres- 
sure if the upper one is more drawn 
upon by wells. 

Attention has been called to the great 
development of alluvial fans and slopes 
about the sides of the valley. The great 
Rio Grande fan occupies a fourth or 
more of the whole extent of the valley 
bottom. From the figures which have 
been given of the depth to the first flow 
at various points on this fan it is evi- 
dent that the configuration of the up- 
permost aquifer agrees closely with the 
surface of the fan, at least within the 
limits of the artesian basin. The forma- 
tion of the fan up to the horizon of 
the upper water-bearing sand must 
therefore have gone on step for step 
with the deposition of the Alamosa 
formation. In other words, the flat 
alluvial fan of the Rio Grande, with 
the exception of the gravel veneer, 
is of sublacustrine deposition, and the 
fans of the other streams on the west 



Santa Fe formation 



LIMIT OF 

"flowing wells 



HUBBARD'S WE'LL 



OTTOWAY'S WELL 



ALAMOSA WELL 



QEO-RQE NEWSOIH'S WELL 



CALKINS WELL 



46 THE SAN LUIS VALLEY, COLORADO. 

side of the valley are largely of the same origin. The persistency and 
continuity of the thin beds of sand and clay making up the Alamosa 
formation show that this deposition was in the quiet water of the 
lake at some distance from the mouths of the streams. Near the 
stream mouths the sedimentation would naturally take on the shifting 
character of delta formation. If sediments of this character occur in 
the Alamosa formation, they are to be expected in the highest part 
of the fans and on the border of the artesian basin. 

Though it does not exhibit the close relation of topography and 
structure shown by the Eio Grande fan, the alluvial slope along the 
west base of the Sierra Blanca is nevertheless shown, by the occur- 
ence of artesian water well up the slope, to be made up of the alter- 
nating clays and sands of the Alamosa formation. Aside from a 
certain lack of correspondence, as shown by the topographic map, 
between the topography and the limit of the flowing-well area, there 
is no apparent reason for distinguishing between the age of the fans 
and that of deposits of the valley proper. The deposit of gravel that 
veneers the upper portion of the alluvial fans and slopes is probably 
more recent than the body of the fans. The section (fig. 3) and the 




Figure 4. — Diagram to illustrate the structure of the artesian basin and the alluvial slope and to indicate 
the relation of the glacial moraines to the slope. 

diagram (fig. 4) illustrate how the glacial moraines of the Blanca 
Mountains are superposed upon the crests of the fans, which are thus 
plainly shown to antedate the ice period. The moraine of Zapato 
Creek is especially well calculated to bring out this relation, because, 
as explained on a previous page, almost all the postglacial erosion 
of Zapato Creek has been limited to the north edge of the fan, leaving 
the front of the moraine surmounting the alluvial fan, practically as 
it was disposed by the advancing ice tongue. 

The age of the Alamosa formation is thus seen to be preglacial and 
post-Miocene. From the Santa Fe formation it was separated by a 
period of deformation, which was followed by the outpouring of an ex- 
tensive series of extrusive lavas, followed in turn by an erosion interval 
of unknown duration. On the other hand, there was apparently no 
break in sedimentation and no erosion interval between the deposition 
of the Alamosa formation and the glacial occupation, which was here 
rather late in the Pleistocene. The logical inference from this is that 
the formation is of late Pliocene or early Pleistocene age. 



GEOLOGY. 47 

As noted in the section of Hansen Bluff on a preceding page, the 
stratum of olive-green clay yielded a great number of shells. These 
were referred to Dr. W. H. Dall, who gives the following list of forms: 

Planorbis parvus Say. Lymnsea desidiosa Say. 

Planorbis trivolvis Say. Valvata lewisii Currier. 

Occurring with these forms are countless numbers of minute valves 
of an entomostracan not identified. 

Shells similar to these are reported as brought up in drillings all 
over the valley. Small hollow white bones, also brought up, are 
usually referred to as "fish bones" or "bird bones." Bits of wood, 
rootlets, leaves, seeds, and peaty moss are reported from all over the 
valley, particularly from the Mosca-Hooper district, which yields the 
tinted water. 

The species enumerated above are all fresh-water forms, and while 
such an assemblage has in general been referred to the Quaternary, 
it may equally well be referred to the Pliocene and thus offer no 
inherent objection to the classification of the Alamosa, on strati- 
graphic grounds, as either late Pliocene or early Pleistocene. 

QUATERNARY DEPOSITS. 

The Recent deposits of the valley comprise sand dunes, alluvial 
fans, alluvium, and alkali-lake deposits. 

SAND DUNES. 

Incipient dunes occur all over the valley, gathering behind clumps 
of brush, fence rows, or whatever else offers a wind-break. A par- 
ticularly sandy area with many small dunes lies south of the Rio 
Grande between Alamosa and Parma station. Another area lies 
between Alamosa and Mosca, extending northeastward in the direc- 
tion of San Luis Lake. The trough of the valley from the railway 
near Washington Springs northward to Dune station is one succes- 
sion of small brush-crowned hillocks with interspersed bare places. 
The latter in the wet season become the sites of ponds and lakelets. 
Each small lake has an embankment on the north and east shores as 
a result of the lodgment in the vegetation there of sand picked up 
by the prevailing southwest wind in its clear sweep across the dry 
bed and shores of the lake. The San Luis Lakes have such embank- 
ments 20 feet high and the Russell Lakes have them in proportion. 
The alluvial slope at the west base of the Sangre de Cristo Range has 
much drifting sand and many incipient dunes scattered from Zapato 
Creek as far north as San Isabel Creek. 

The great development of sand dunes, however, is between 
Medano and Sand creeks, where an area of over 40 square miles is a 



48 THE SAN LUIS VALLEY, COLORADO. 

solid expanse of dunes, some of which reach great size, as shown in 
Plate VIII. These dunes consist of rather coarse white quartzitic 
sand with which is mixed a varying proportion of darker and 
heavier sand, the latter consisting largely of magnetite, with pre- 
sumably a proportion of those rare earths ordinarily found in black 
sands. Several attempts have been made at placer mining in the 
area but are reported as having been given over on account of the 
difficulty in bringing water to the deposits. Assays are reported to 
have shown the darker sands to be high in auriferous magnetite. Be 
that as it may, it seems undeniable that the sands of the dune area 
contain a larger proportion of the heavier material than the sand of 
the valley. 

Hayden, as noted, classed the dunes as a remnant of the Santa Fe 
formation. Endlich a advanced the theory that the sand came 
across the valley from the mountains on the southwest, being driven to 
its present locality by the prevailing southwest winds, and that it was 
especially collected in the reentrant angle in the mountain front near 
Mosca Pass as an effect of eddying currents in the winds, caused by 
the low gaps in the mountains near this point. 

That the sands of the valley are shifting northeastward under the 
influence of the winds is shown by the long sandy area along the 
western alluvial slope of the Sangre de Cristo Range and by the 
embankments of sand on the north and east shores of the lakes and 
ponds. That the accumulations of the great dune area are so derived 
is open to question. It has been pointed out that the sand of the 
dune area averages much heavier than that of the valley in general. 
In accumulations under such wind transportation and sorting, the 
reverse would occur. It seems much more reasonable to conclude 
with Hayden that there was here a remnant of the Santa Fe forma- 
tion, without the protection of interbedded or overcapping lavas, 
which has been broken down by the winds, and its sands, whipped 
now forward and now backward, possibly augmented by contribu- 
tions from the valley, have been built up into the dunes we now see. 

ALLTTVIAL FANS. 

It has already been shown that the alluvial fans and slopes were 
essentially completed in preglacial time and that they are prob- 
ably Pliocene or early Pleistocene in age. But over their surface is 
a covering or veneering of gravel which must have been largely 
increased in glacial time and since. 

In the description of the topography of the valley (p. 11) reference 
was made to low bluffs or terraces, not now adjacent to streams, 
which were explained as old courses of the streams or their distribu- 
taries abandoned in their wanderings over the alluvial fans. These 

a Ann. Rept. U. S. Geol. and Geog. Survey Terr., 1875, p. 143. 



GEOLOGY. 49 

and the configuration of the fan itself seem to have been interpreted 
by various writers as due to former courses of the Rio Grande. Car- 
penter a alludes to the "ancient course" of the Rio Grande, but does 
not locate it on the accompanying map. Hinton 6 describes and 
maps the old course as leaving the present river above Del Norte, 
skirting the foothills with a due northeast course to the trough of the 
valley, which it followed southward, uniting with the present course 
of the Rio Grande near Hansen Bluff. The course northeast from 
Del Norte, as outlined on the map, corresponds to the north edge of 
the Rio Grande alluvial fan. Doubtless the Rio Grande or some 
distributary in times past took the course along the north edge of the 
fan, just as the river at present occupies a course along the south 
edge of the fan, and just as it must have occupied all the intervening 
territory, wandering backward and forward across it. In this way 
it must have deposited the gravel and sandy covering of the fan, in 
the fashion which may be seen after a shower where a gully in a steep 
slope strikes a more level space and the streamlet drops part of its 
load and builds up a little alluvial fan. But a wrong impression is 
conveyed by alluding to it as "the" former course if that is meant to 
imply that the Rio Grande has had but two courses, that one and the 
present one. 

Endlich c outlines a former course of the Rio Grande, leaving the 
present course of that river 3 miles above Alamosa, circling north of 
Washington Springs, crossing the railroad near Baldy station, crossing 
Trinchera Creek south of that station, crossing the Rio Culebra about 
6 miles west of San Luis, and rejoining the present course some 15 
miles below the New Mexico line. A glance at the topographic map 
will show the utter improbability of this supposition. Baldy station 
is 60 feet higher than the point on the river where the old course is 
supposed to leave and the divide south of Trinchera Creek is 50 feet 
higher still. 

ALLUVIUM. 

Alluvial bottoms occur along the Rio Grande and its various tribu- 
taries as well as along the other streams which enter the valley but do 
not reach that river. The width of the alluvium along the Rio Grande 
varies from 1 to 2 miles, with here and there reaches of gravelly and 
sandy loam. The habit of the smaller streams to divide into distribu- 
taries reuniting again lower down, forming "sloughs" or "bayous," 
has a tendency to make the alluvial areas of those streams wider than 
they would otherwise be. 

a Bull. Colorado Agr. Coll. Exper. Sta. No. 16, p. 18. 

b Report on irrigation and the cultivation of the soil thereby: Sen. Ex. Doc. No. 41, 52d Cong., 1 sess., 
pt. 1, p. 151. 

c Ann. Rept. U. S. Geol. and Geog. Survey Terr., 1875, pp. 147, 148. 

42120°— wsp 240—10 4 



50 THE SAN LUIS VALLEY, COLOEADO. 

ALKALI-LAKE DEPOSITS. 

There are many small ponds over the valley which in the dry season 
are pretty well saturated with alkali, exhibiting a white crust along 
the shore and upon any object projecting above the surface of the 
water, but in the SW. j SW. J sec. 30, T. 40 N., R. 12 E.,10 miles east- 
southeast of Hooper, there is a small lake about an acre in extent 
which is practically solid crystallized sodium carbonate. The lake 
has the appearance of being frozen and covered with a thin fall of 
drifted snow. A view of it is shown in Plate'IV, B. 

This deposit has been examined by Dr. Herman Fleck, of the Colo- 
rado School of Mines, and from his report the following facts are taken 
by the courtesy of Mr. Mark Woodruff, receiver of Colorado state lands : 
The soda is quite pure, except for a certain amount of dust, including 
some organic matter, blown into the deposit by the wind and amount- 
ing in the average sample to about 15 per cent. The average thickness 
of the soda is about 18 inches, with a maximum of 30 to 48 inches, and 
it is estimated that 4,000 tons of soda remains in sight in the lake. 
About 500 tons has been raised and shipped. As the soda was re- 
moved, the space filled with the mother liquor, from which soda is 
again crystallizing. How long this would continue and to what extent 
solid soda exists beneath the surface are questions as yet unanswered. 
The soda, though originally derived by solution from the crystalline 
rocks of the mountains, probably has its immediate origin in the clays 
and soils of the valley, from which it has been leached and concen- 
trated, as are the alkali crusts that trouble the farmer. The reason 
for the especially strong condensation at this single point probably 
lay in some topographic relation now altered and concealed by the 
shifting dunes of this portion of the valley. 

W. P. Headden a has also examined the soda lake and made 
analyses of the deposit and the mother liquor, of the surface water and 
alkali incrustations, and of the tinted alkaline artesian waters of the 
Mosca-Hooper district. He found that the mother liquor of the soda 
lake and the tinted artesian waters have the alkalies and other ele- 
ments in common and in like proportion, differing in those respects 
from the surface waters and the alkali incrustations. He concludes 
that the soda deposits have been derived in some way from the tinted 
artesian waters. 

GEOLOGIC HISTORY OF THE SAN LUIS VALLEY. 

The area occupied by the San Luis Valley was originally included 
in the eastern portion of the Sawatch land mass, the eastern shore line 
of which corresponded in position to the Sangre de Cristo-Culebra axis. 
Upon this shore line, through Paleozoic and Mesozoic time, had been 

a Am. Jour. Sci., 4th ser., vol. 27, 1909, pp. 305-315. 



GEOLOGY. 51 

deposited great thicknesses of limestones, sandstones, and conglom- 
erates. As in other places where a shore line received heavy deposits, 
it became a line of weakness, and succumbing to the pressure was 
folded by stages into the towering Sangre de Cristo and Culebra 
ranges. Correlated with the uplift of the range was a depression of 
the valley apparently either by a synclinal fold, or by a great fault 
along the west border of the range, or more probably by a combina- 
tion of the two. The details of the time and the stages of this sequence 
of events must wait for final solution until the geology of the east and 
west ranges is more intimately known. Interesting discussions of the 
orographic development of the Rocky Mountains, incidentally dealing 
with the history of the San Luis Valley region, have been given by 
S. F. Emmons and R. C. Hills (see bibliography, p. 8), to whose 
papers the reader is referred. 

The first stage in the history of the valley of which any record 
is left in the formations of the area is the period when the depo- 
sition of the Santa Fe formation began. At this stage the depres- 
sion consisted of a broad valley limited by the Sangre de Cristo and 
Culebra ranges on the east and probably extending considerably 
farther westward than the limits of the present valley. This depres- 
sion opened to the south along the valley now occupied by the Rio 
Grande. In this depression in late Miocene time there was laid 
down the succession of sands, conglomerates, tuffs, andesites, and 
basalts which make up the Santa Fe formation. At the close of 
deposition the valley probably presented the appearance of a bolson 
valley sloping to the center from the height of the San Pedro Mesa, 
the Garland Mesas, and the great sand dunes on the east side of the 
valley, and from well up on the range on the west side of the valley. 
From vents around the west and south margins of the valley that had 
furnished the flows interbedded with the sands and conglomerates 
there was poured out on this plain a sheet of dark andesitic lava, which 
covered the deposits on the west side and over the whole south half of 
the valley but did not reach those on the east side of the valley north 
of Fort Garland. Succeeding this flow there was apparently a down- 
warping of the central valley, with faulting in a northeast-southwest 
direction in the vicinity of the northwest face of the San Luis Hills, 
the downthrow being to the northwest and carrying the top of the 
Santa Fe formation to a depth of more than 1,000 feet in the center 
of the valley. Accompanying or following these movements was an 
extrusion of the basaltic cones and table-top mountains which com- 
pose the San Luis Hills. Presumably at this time also occurred the 
extrusion of those masses which, as Los Mogotes Peak, Chiquita Peak, 
and other prominent points and cones on the west and south sides of 
the valley, rise above and apparently through the Santa Fe formation; 
though it is possible that these points mark as well the vents through 



52 THE SAN LUIS VALLEY, COLOKADO. 

which have come some of the interbedded lavas of the Santa Fe forma- 
tion. 

In the depression caused by the down warping in the center of the 
valley there was formed an extensive fresh-water lake, in which was 
deposited the series of sands and clays that make up the Alamosa 
formation. On page 81 it is shown that this sedimentation was inter- 
rupted by arid periods, when the lake shrank to a small size, was 
more or less alkaline, and supported considerable vegetation, princi- 
pally moss. These deposits of alkali and organic matter, covered by 
later beds of clay and sand, are the source of the gas and the color 
of the tinted waters of the Mosca-Hooper district (pp. 81-82). 

So far as may be seen, no change in the attitude of the valley 
has ensued since the close of deposition of the Alamosa formation. 
When the trough of the valley had been filled with that series of 
sands and clays to the height of Hansen Bluff the overflow of the 
lake in which they were deposited had cut down the outlet through 
the San Luis Hills south of Los Sauces village nearly to the level of 
the bluff, and the drawing off of the lake followed. Further erosion 
has cut the outlet some 60 feet deeper and carried away that depth 
of the Alamosa formation along the Rio Grande adjacent to the 
bluff. 

Nearly one hundred years ago Jacob Fowler, trapper and ex- 
plorer, entered the San Luis Valley from the south. The following 
excerpt is the entry made in his journal a on the evening of his arrival 
in the valley. The lines italicized by the present writer show how 
clearly this observant trapper grasped the character and later 

geologic history of the valley: 

monday 18th Feby 1822 
We Sot out Early up the River and at about 12 miles Came to the upper Eand of the 
High Rocks and going down a gradual decent three or four Hundred yds Came to a low 
Bottom on the River the Bank being low not more than six or Eight [feet] High the River 
butifull and a bout one Hundred yds Wide — But all frosen up tite — We Heare got 
Watter for the Horses — it is Heare proper to Remark that the River as far as We Have 
Seen it pasing down betwen the High Rocks or mountains — dose not move in a very 
gentle manner as It appears much Impeded by the Rocks falling from Each Side, and 
is f orsed forward dashing from one Rock over others In almost one Continued foam the 
Hole distance threw the mountains Which from What I Can larn is about seventy 
miles When it appeers below In an oppen Cuntry — I Have no doubt but the River from 
the Head of those Rocks up for about one Hundred miles Has once been a lake of about 
from forty to fifty miles Wide and about two Hundred feet deep — and that the running 
and dashing of the Watter Has Woren a Way the Rocks So as to form the present Chanel — 
We this day Crosed a dry Branch. But Have not Seen one Streem of Watter In all 
the distance We Have Came up on the [west] Side We traveld nor Cold our Horses 
get one drop of Watter in all that distance but the Eat Snow When the Cold get it. 

Stevenson 6 was strongly of the belief that "the whole character 
here seems to admit of no inference other than that the valley is 

a The journal of Jacob Fowler, 1821-22, edited by Elliott Coues, New York, 1898, pp. 112-114. 
b Rept. U. S. Geog. Surveys W. 100th Mer., vol. 3, 1875, pp. 460, 462. 



GEOLOGY. 53 

the result of glacial erosion. * * * It seems not impossible that 
the glacial mass was of equal extent (with the ancient lake) and that 
in its retreat it delayed for a time, its foot occupying the line marked 
by the abrupt wall forming the southern boundary of the present 
basin." 

Endlich ° rejected this view and maintained that the effects of 
glacial modification were restricted to the immediate edges of the 
valley, in which limitation the present writer fully concurs. It has 
been noted in the preceding pages that the valley glaciers in the 
eastern range reached only to the crests of the alluvial fans and that 
even in the larger streams of the west ranges they did not reach that 
far. If, with exceptionally favorable gathering grounds in the high 
Sangre de Cristo Range, the valley glaciers no more than reached the 
upper margin of the alluvial slope, it is not probable that a great 
glacier could gather in the valley. 

Since the draining of the lake in which the Alamosa formation was 
deposited, sedimentation in the valley has been limited to the deposi- 
tion of alluvium along the valley and of gravel veneering on the allu- 
vial cones and slopes. On the whole, the amount of deposition since 
the glacial period seems to have been inconsiderable. The Zapato 
fan, where the discharge of the creek has been confined since glacial 
time to the north edge, has received no perceptible addition, but 
rather has been reduced by erosion. 

The impression prevails locally that the Sangre de Cristo Range is 
younger than the mountains west of the valley. This impression 
has probably arisen from the notion that the level valley is a con- 
tinuation of the Great Plains east of the Front Range of the Rocky 
Mountains and that the oceanic waters which deposited the plains 
formations washed the base of the western ranges until the Sangre de 
Cristo Range was upheaved and cut the valley off from the sea. 
Possibly the gentler outline and older aspect of the western ranges 
have contributed to the impression. It has been made plain in the 
preceding pages that the western ranges adjacent to the valley are, 
in part at least, composed of the youngest formation but one in the 
region, and that this was deposited long after the Sangre de Cristo 
was elevated. However, the depression of the Santa Fe formation 
in the center of the valley and certain warping in that formation 
northwest of Fort Garland may have been accompanied by a further 
elevation of the Sangre de Cristo Mountains. This possibility is 
strengthened by the attitude of the lava flows covering the Raton 
Mesa and others east and south of Trinidad. These flows, according 
to information communicated by Mr. W. T. Lee, spread over the 
beveled edges of formations ranging from Dakota to post-Laramie 
in age and are themselves of Tertiary age. They have been elevated 

a Ann. Rcpt. U. S. Geol. and Geog. Survey Terr., 1875, p. 223. 



54 THE SAN LUIS VALLEY, COLORADO. 

slightly, tilted away from the Culebra Range, indicating a rise of 
that range, and later dissected. It is reasonable to suppose that the 
elevation of the range which accompanied the deformation of these 
Tertiary lavas on the east side was contemporaneous with the 
deformation of the Santa Fe formation on the west side of the range. 
In conclusion, the essential harmony of the local history herein set 
forth with the general history of the West for the same time may be 
recapitulated: Miocene deposition, unconformable below, of a series 
of sands, gravels, and interbedded lavas and tuffs, followed by oro- 
graphic movements and additional volcanic activity, succeeded by 
quiet deposition of sands and clays in fresh-water lakes, passing 
without stratigraphic break into Pleistocene and Recent deposits. 

UNDERGROUND WATERS. 

GENERAL CONSIDERATIONS. 

PREREQUISITE FEATURES OF AN ARTESIAN SYSTEM. 

The essentials of an artesian system are few and simple : 

1. An inclined stratum, as of sand, which receives water in the 
higher portions and transmits it freely to the lower portions. 

2. Relatively impervious layers, as clay or shale or finer sand, 
which confine the water within the water-bearing bed or aquifer. 

3. Resistance to lateral escape of the water from the lower parts of 
the aquifer greater than its resistance to the ascent of water in the 
well. This may be due to either of several factors, among the com- 
monest of which are — 

(a) The bending up of the beds to form the opposite side of a basin. 

(b) The thinning out of the water-bearing sand bed or aquifer. 

(c) Loss of porosity in the aquifer. 

(d) Frictional resistance to lateral movement within the aquifer 
itself. 

(e) Unconformable depositional contact with less pervious beds, 
as along lower Conejos River. 

APPLICATION TO THE SAN LUIS VALLEY. 

The San Luis Valley is an almost ideal example of the artesian 
basin. The structure of the valley has been already discussed, and 
a cross section of the valley is shown in figure 3. The water occurs in 
beds of fine blue to gray sand varying from 1 to 20 feet or more in 
thickness, separated from one another by beds of blue clay ranging 
from 1 foot to several hundred feet in thickness. In the alluvial slope 
near the base of the mountains at the margin of the valley the clay 
beds thin out, the lowest ones usually reaching the farthest and high- 
est up the slope, thus giving the greatest pressure to the flows beneath 



UNDERGROUND WATERS. 55 

them, where they are penetrated out in the valley. If all lower open- 
ings and avenues of escape in the aquifers were stopped, the water 
would rise to the level of the receiving area, or, rather, to the lowest 
point in that area. Thus the water in the strata penetrated at Ala- 
mosa would have sufficient head or be under sufficient pressure to rise 
as high as the margin of the basin about Monte Vista, which would be 
about 100 feet above the surface at Alamosa. As a matter of fact the 
head of the Bucher well at Alamosa, the deepest in that vicinity, is 
not over 56 feet, and the greater number of wells reaching a depth of 
about 700 feet have a head of less than 40 feet. This loss of head is 
partly due to the drain upon the water bed by other wells but is 
probably due chiefly to loss by lateral flow where the sands of the 
Alamosa formation come into contact with the Santa Fe formation 
along the northwest margin of the San Luis Hills. In support of this 
suggestion may be cited the fact that wells near the mouth of Conejos 
River, in the very lowest portion of the artesian basin, instead of 
having the very strongest pressure in the valley, as they theoretically 
should, have on the contrary but small pressures, though very good 
flows. 

SOURCE OF THE ARTESIAN WATER. 

The source of supply of the artesian water in the San Luis Valley is 
unquestionably the mountain streams which flow down across the 
alluvial slope. The disappearance of the mountain streams soon 
after they reach the alluvial slopes is a matter of common observation. 
This is particularly true of the streams flowing from the Sangre de 
Cristo Range. Very few of these streams get beyond the pinons 
which cover the upper part of the alluvial slope. The same is true of 
the streams on the west side of the valley, though the greater number 
of the streams there, being much longer and larger than any in the 
Sangre de Cristo Range, have sufficient volume of water to stand the 
loss in passing across the alluvial slope and to send a considerable flow 
to the Rio Grande, especially in the wet season. But all these 
streams suffer noticeable loss in the region of the gravel slope. 

The largest stream entering from the west is, of course, the Rio 
Grande, and along this stream various discharge measurements have 
been made with a view to showing the loss by seepage of this river in 
various portions of its course through the valley. As shown by these 
gagings, a the actual loss by seepage of the Rio Grande between Del 
Norte and Monte Vista, a distance of 15 miles, is 75 second-feet. No 
other section of the river shows a loss at all comparable to this; in 
fact, the remainder of its course for the most part shows a gain from 
seepage. Discharge measurements of various other of the principal 

a Bull. Colorado Agr. Coll. No. 48, p. 30. 



56 THE SAN LUIS VALLEY, COLORADO. 

streams on the west side of the valley have been made from time to 
time by the state engineer of Colorado, the results of which show like 
losses in the region of the alluvial slope. 

ADEQUACY AND PERMANENCY OF SUPPLY. 

It has been explained on a previous page that the artesian supply 
has the first call upon the water of the Rio Grande, inasmuch as one 
of the large ditches, which has the earliest priority of all, takes its 
water from the Rio Grande below the section which supplies water to 
the artesian basin. Since this priority must be satisfied before any 
water is taken out above, there will always be water flowing across the 
area which supplies the artesian basin when there is any water in the 
river at all. This is largely true of the other streams as well. There- 
fore the artesian basin will always be supplied with water, and any 
question of failure of wells in the valley will be one of mutual inter- 
ference as a result of too great concentration of wells, and not one of 
expansion of the irrigation systems. 

CAPACITY. 

In 1891 Professor Carpenter, estimating 2,000 wells in the valley, 
with an assumed average flow of 25 gallons per minute, found the 
total artesian flow to be about 110 second-feet. At 70 acres to the 
second-foot, this volume of water, if all used, would irrigate 7,700 
acres. 

Since that year many new deep wells have been bored and older 
ones sunk to deeper and heavier flows, so that the average flow is 
now greater than at that time. By actual count, the wells shown on 
the map and plats herewith number 3,234. The average flow of 
1,000 measured and estimated 2 and 3 inch wells, excluding those 
in towns, amounts to 40 gallons per minute. The wells of the towns 
have in general much smaller flows than those in the country, but it 
is believed that the large flows of the wells over 3 inches in diameter, 
which are not included in the average, will offset the small flows of 
the town wells, and that the average of 40 gallons is a fair one. Flow- 
ing at this average, the 3,234 wells in the valley will yield a volume 
of water equal to 286 second-feet. At the rate of 70 acres to the sec- 
ond-foot this volume of water will irrigate 20,000 acres. This esti- 
mate of the duty of water is probably a minimum. On the average 
it is perhaps 25 per cent too small, so that 25,000 acres is nearer a 
true estimate. With adequate storage, this volume of water could 
be made to irrigate two or three times as great an acreage. 

It is practically impossible to estimate the acreage actually irri- 
gated from artesian wells unless a painstaking census be made with 
that object in view. Even so, it would be impossible to get accu- 
rate figures, inasmuch as many persons use the flow of the wells 



FLOWING WELLS. 57 

in connection with the ditch water. In the absence of such actual 
figures of acreage irrigated from artesian water, some estimate, such 
as has been made of the possible irrigation from artesian water, must 
serve. The only wells not used at all in irrigation, a small percentage 
of all the wells of the valley, are those used for stock purposes. 
They are scattered here and there over the un tilled land, and the 
water from them usually sinks within a short distance of the well. 
The larger wells are almost without exception used for purposes of 
irrigation. In 1904 there were in the valley 76 6-inch wells, with an 
average flow of over 300 gallons a minute, and 77 wells over 3 inches 
and under 6 inches in diameter, with an average flow of about 175 
gallons a minute. The total flow of these larger wells was approxi- 
mately 80 -second-feet. 

However, the true value of artesian water for irrigation purposes 
is not to be reckoned by the flat acreage it is capable of irrigating. 
The special value of artesian water lies in the steady, unfailing supply 
in times of drought when ditch water is wanting. 

FLOWING WELLS. 

MARGINAL REGION. 

ALAMOSA AND VICINITY. 

This district includes the wells in the town of Alamosa and those 
southeastward along the Rio Grande for several miles, as well as those 
north and east of the town, within a radius of 6 or 7 miles. The dis- 
trict contains some of the largest and most of the deep wells in the 
valley. Within the town itself, covering 1 square mile (PL IX), 
there are 140 wells, the greater number of which are about 700 feet 
deep or within 50 feet more or less than that depth. 

The Bucher well, on the other side of the Rio Grande from Alamosa 
but in the northeast corner of the same section, is one of the oldest 
as well as one of the deepest wells in the valley. This well, sunk in 
1889, is nearly 1,000 feet deep. The main flow was secured at a 
depth of 932 feet and the smaller flow at 500 feet, the combined flow 
in 1891 being reported by Professor Carpenter to be about 600 gal- 
lons a minute, or 1J second-feet. The diameter of the well is 6 inches 
at the bottom. Reduced to 3 inches, it throws a jet of water 48 
inches high. The temperature is 74.7 ° a , according to Professor Car- 
penter, who reports that the pressure indicates a head of 56 feet. No 
record was kept of the geologic section of the well. Analyses of the 
water are given in the table of analyses on page 112. The water is 
without taste, like that of shallower flows. It is caught in a large 
reservoir and used in a small way for irrigation. A view of this well 
is shown in Plate VII, A. 

a All temperatures here given are expressed in degrees Fahrenheit. 



58 



THE SAN LUIS VALLEY, COLORADO. 



The town well, situated in the northwest corner of Alamosa, a mile 
west of the Bucher well, is 865 feet deep and 6 inches in diameter and 
is cased to a depth of 852 feet. The flow in 1891, as measured by 
Professor Carpenter, was 400 gallons a minute. The temperature 
is 72° F. The water from this well, with additions from the various 
private wells, is carried in ditches through the streets of the town,, 
irrigating the shade trees and grass plats along the way. The follow- 
ing is a condensed record of the well : 

Record of Alamosa town well. 



Recent: 

Alluvial soil 

Sand 

Alamosa formation: 

Blue clay 

Black sand (flow) 

Blue clay 

Black sand (strong flow) 



Thick- 
ness. 



Feet. 
3 
10 

511 

2 

324 

15 



Depth. 



3 
13 

524 
526 
850 
865 



The Denver and Rio Grande Railroad well at the water tank is 938 
feet deep and 4 inches in diameter at the bottom. It has a flow of 
60 gallons a minute at the surface of the ground, or 20 gallons a min- 
ute where it empties into the tank at a height of 37 feet above the 
ground. The pressure, when finished, indicated a head of 46 feet. 
A small flow was struck at 630 feet, and at 838 feet a flow of 90 gal- 
lons a minute, the pressure of which indicated a head of 32 feet. The 
purpose of going on to the deeper though smaller flow was to get 
sufficient head to lift the water into the top of the water tank at 37 
feet. The flow at 937 feet is the same flow that is struck by the 
Bucher well. These two are the only wells having this flow in the 
vicinity of Alamosa, though there are a few other wells deep enough 
to reach it. The log of the well is as follows : 

Record of Denver and Rio Grande Railroad well. 



Thick- 
ness. 



Depth. 



Recent: 

Soil 

Sand 

Alamosa formation: 

Clay 

Sand 

Clay 

Sand 

Light clay with streaks of sand.. 

Blue clay with some sand strata 

Sand (small flow) 

Clay with some sand strata 

Sand (strong flow) 

Hard clay 

Sand (flow) 

Hard clay 

Hard layer 

Sand and gravel (strong flow). 



Feet. 
3 
15 

3 

9 

18 

6 

296 

280 

2 

206 

10 

72 

2 

13 

2 



Feet. 



3 

18 

21 

30 

48 

54 

350 

630 

632 

838 

848 

920 

922 

935 

937 



U. S. GEOLOGICAL SURVEY 



WATER-SUPPLY PAPER 240 PLATE 




PLAT OF ALAMOSA, SHOWING LOCATION OF WELLS. 



FLOWING WELLS. 



59 



The Goodall well, 400 feet southeast of the Bucher well, is reported 
to have this section: 

Record of Goodall well. 



Recent: Surface gravel and sand 

Alajnosa formation: 

Yellow clay 

Black sand 

Blue clay 

Black sand (first flow, light) 

Blue clay 

Black sand (second flow, light) 

Blue clay 

Black sand (third flow, light) 

Blue clay 

Red sand (fourth flow, good) 

Blue clay 

Red sand and small gravel (fifth flow, good) 



Thick- 
ness. 


Depth. 


Feet. 


Feet. 


40 


40 


15 


55 


1 


56 


204 


260 


1 


261 


245 


506 


1 


507 


109 


616 


1 


617 


159 


776 


10 


786 


90 


876 


7 


883 



This well is 3 inches in diameter and the temperature is 70°. The 
flow is the large one struck in the town well and at 838 feet in the 
Denver and Rio Grande Railroad well at the water tank. 

The Spriesterbach well, in the northern part of Alamosa, 725 feet 
deep and 3 inches in diameter, has a temperature of 66°. The well 
has recently failed considerably. It seems likely, as indicated by the 
temperature, that the water is coming from a flow somewhat above 
the bottom. The detailed geologic section of this well has been given 
on page 41. Analysis shows the water to contain 295 parts per million 
total solids. 

The Hirst well, in the southern part of Alamosa, is 4 inches in diam- 
eter, 820 feet in depth, and cased to bottom. The following flows 
are reported : 

First flow, 220 feet, stream size of lead pencil. 
Second flow, 475 feet, stream 1 inch in diameter. 
Third flow,' 680 feet, good flow. 
Fourth flow, 800 feet, heavy flow in 8-10 feet red sand. 

The Alamosa Milling and Elevator Company's well is 4 inches in 
diameter and 680 feet deep, cased to the bottom. The temperature 
of this well is 69° and that of a deeper 3-inch well is 72°. An analysis 
of the water will be found in the table of analyses, page 112. 

At the electric-light plant there is a well cased 6 inches for some 
distance and 4 inches to the bottom at 800 + feet. The temperature 
is 73°. 

The Fritz Emperius well is a mile and a half southeast of Alamosa, 
in the NW. \ sec. 13, T. 37 N., R. 10 E. The depth is 810 feet, cased 
to the bottom, and the diameter is 4J inches. The temperature is 72° 
and the flow forms a jet 7 \ inches above the casing. The flow is 
estimated to be about 350 gallons a minute and, stored in a reservoir, 
will irrigate 50 acres. The cost was $950. 



60 



THE SAN LTJIS VALLEY, COLORADO. 



The Wilkins well, a mile southeast of Alamosa, in the SE. J sec. 14, 
T. 37 N., R. 10 E., is 800 feet deep, cased to the bottom, and is 5J 
inches in diameter. It is reported to have a flow rising 7 inches above 
the casing. The temperature is 72°. 

Three miles down the Rio Grande from Alamosa, on the Wilkins, 
Schwartz, and Worcester ranches, there are several 4, 4J, and 5 inch 
wells that have good flows. 

At the Blanca farm, 4 miles north of Alamosa, in the southeast 
corner of the NE. \ sec. 21, T. 38 N., R. 10 E., there is a 3-inch well, 840 
feet deep, cased to the bottom. The flow, struck in gravel, throws a 
jet 6| inches above the casing, and is estimated to be 130 gallons per 
minute. The temperature is 72° and there is a slight taste of sulphur. 
The analysis of the water is given in the table on page 112. 

On George Newsom's ranch, 5 miles northeast of Alamosa, in the 
SW. | sec. 33, T. 38 N., R. 11 E., there are eight 3-inch wells, two 
4-inch wells, and one 6-inch well, all with fair flows. The geologic 
section, which is typical for this vicinity, is as follows : 

Section of Newsom wells. 



Thick- 
ness. 



Depth. 



Recent: 

Soil and clay 

Gravel and sand (cased to this level) 
Alamosa formation: 

Clay 

Sand (first flow) 

Clay 

Sand (second flow) 

Clay 

Sand (third flow) 

Clay 

Sand (fourth flow) 

Clay 

Sand (fifth flow) 

Clay 

Sand (sixth flow) 



Ft. in. 
16 
10 

74 

4 
25 

5 

34 

1 

64 

1 4 

124 

2 

48 

4 



Feet. 



16 
26 

100 
100 
125 
126 
160 
161 
225 
226 
350 
352 
400 
404 



HENRY STATION AND VICINITY. 

This district is characterized by the greatest number of wells of 
large bore in the valley. The number of 6-inch wells in this vicinity 
and westward in the Fountain neighborhood is over 50, and in 
addition there are several 4-inch and 5-inch wells. All these larger 
wells have been put down for purposes of irrigation, many of them 
recently. Twelve of these have been recently put down on the 
Empire farm of the Southern Colorado Land Company, in the imme- 
diate vicinity of Henry station. The following section of one of 
these is typical of the region: 



U. S. GEOLOGICAL SURVEY 



WATER-SUPPLY PAPER 240 PLATE X 




A. SIX-INCH WELL ON EMPIRE FARM. 




■immmi.n»" 



B. KINCH WELL. 



FLOWING WELLS. 

Section of Empire farm well. 



61 



Thick- 
ness. 



Depth. 



Recent: Surface gravel and loam 

Alamosa formation: 

Clay 

Sand (small flow) 

Clay 

Sand (flow) 

Cfoy 

Sand (flow) 

Clay 

Sand (flow) 

Clay with various beds of sand 

Sand (flow) 

Clay 

Gravel below ("gravel" flow, strong) 



Feet. 
11 



59J 
2 

38 
3 

57 

3 

194 

3 

40 



Feet. 
11 



140 
142 
180 
183 
240 
243 
437 
440 
480 



Another well on the same farm, by a different driller, gives this 

record : 

Section of Empire farm well. 



Thick- 
ness. 



Depth. 



Recent: Gravel 

Alamosa formation: 

Clay 

Sand (first flow) 

Clay 

Sand (second flow) 

Clay with water-bearing sa"nd beds every 20 feet 

Gravel (gravel flow) 

Clay 

Bowlders below (strong flow). 



Feet. 
17 

53 

1 

54 

1 

324 

3 

50-90 



Feet. 
17 

70 
71 
125 
126 
450 
453 
500-545 



This bowlder bed is reached at a depth of 500 feet on the west side 
of the ranch, and at a depth of 545 feet on the east side. A typical 
view of one of these wells in winter is shown in Plate X,A. The 
casing is cut off close to the ground so that the water will not dig out 
a great hole around the well, as it would if the casing extended far 
above the ground. 

Two 6-inch wells on the Mitchell ranch, in the SE. J sec. 33, T. 37 
N., R. 10 E., have depths of 540 and 575 feet. Each throws a 
3-inch jet and together the flow is If second-feet, irrigating 100 acres. 
They are cased only to the first clay and the total cost of both was 
$233. 

A well on the Adams ranch, 3 miles due east of Henry station, in 
the southeast corner of the SW. { sec. 35, T. 37 N., R. 10 E., furnishes 
the following section: 

Section of Adams well. 



Recent: Surface gravel and loam 

Alamosa formation: 

Clay 

Sand 

Clay, with water-bearing sand beds 2 feet or so in thickness about every 40 feet 
Gravel below (heavy flow). 



Thick- 
ness. 



Feet. 
20 



40 

1 
U19 



Depth. 



Feet. 



20 

GO 
61 

080 



62 



THE SAN LUIS VALLEY, COLORADO. 



This well, 6 inches in diameter, bored in November, 1892, is re- 
ported to have had originally a jet 9 inches high. By 1904 the jet 
was reduced to 3£ inches. 

On the J. W. Kinch place, in the NE. J sec. 9, T. 36 N., R. 9 E., a 
6-inch well, when new, had a jet of 12 inches, which is now reduced to 
5^ inches. A section of this well is as follows: 

Section of Kinch well. 



Thick- 
ness. 



Depth. 



Recent: Surface gravel and loam 

Alamosa formation: 

Clay 

Black sand (first flow) 

Clay 

Sand (second flow) -. 

Clay, with water-bearing sand beds 2 to 4 feet thick every 40 or 50 feet 

Gravel and coarse sand (gravel flow) 



Feet. 
14 

66 
1 

44 

2 

260 

15 



Feet. 



80 
81 
125 
127 
387 
402 



This well is shown in Plate X, B. 

FOUNTAIN NEIGHBORHOOD. 

In the SE. \ sec. 16, T. 37 N., R. 9 E., on the place owned by George 
Ottaway, there are two 6-inch wells, dug in 1900 and 1901. The 
south well, 585 feet deep, has this section: 

Section of Ottaway luell. 



Thick- 
ness. 



Depth. 



Recent: Surface clay and gravel 
Alamosa formation: 

Blue clay 

Sand (.first flow, very weak) 

Blue clay 

Sand (fair flow; 4 feet head) 

Blue clay 

Sand (flow) : 

Blue clay 

Sand (flow) 

Blue clay 

Sand (flow) 

Blue clay 

Sand (flow) 

Blue clay 

Hard yellow clay 

Gravel (gravel flow; 



Feet. 
14 

106 

1 
189 

2 
40 

2 
40 

2 
100 

2 
38 

2 
17 
20 
10 



Feet. 



120 
121 
310 
312 
352 
354 
394 
396 
496 
498 
536 
538 
555 
575 
585 



These wells are reported to have had jets of 5^ inches when first 
put down, but they are now reduced to 2 inches. The temperature 
is 64° and the two wells irrigate 160 acres. 

When wells are sunk to the gravel flow in this vicinity the water 
runs out at the top of the drill rods 22 feet above the surface of the 
ground, showing a head of that much or more. 



FLOWING WELLS. 



63 



The well on the Hubbard place, in the southwest corner of the NE. \ 
sec. 9, T. 37 N., R. 9 E., has the following section: 

Record of Hubbard well. 



Thick- 
ness. 



Depth. 



Recent: Surface clay and gravel 

Alamosa formation: 

White clay 

Blue clay 

Hard streak 

Sand (first flow) 

Soft mud 

Sand (second flow) 

Blue clay 

Sand (third flow) 

Blue clay 

Red sand (fourth flow; heavy) . . 

Blue clay 

Sand (fifth flow) 

Blue clay 

Sand (sixth flow) 

Blue clay 

Sand (seventh flow) 

Hardpan 

Blue clay 

Gravel (eighth flow; gravel flow) 



Feet. 
16 

44 

80 
1 
1 

24 
1 

34 

1 

119 

U 

42§ 
2 

63 
2 
8 
2 
3 

35 
2 



Feet. 
16 

60 
140 
411 
142 
166 
167 
201 
202 
321 
322| 
365 
367 
430 
432 
440 
442 
445 
480 
482 



This vicinity was one of the earliest in which artesian wells were 
sunk for irrigation on an extensive scale, and now over 2,000 acres 
are irrigated from wells alone, besides which much artesian water is 
turned into the ditches and used in conjunction with the ditch water. 

LA JARA AND VICINITY. 

The wells of the La Jara district are of moderate depth and very 
strong flow. In the town itself there are 71 wells, the distribution of 
which is shown in figure 5. These range in depth from 65 to more 
than 300 feet. The following section is reported to be typical: 

Section of well at La Jara. 



Thick- 
ness. 



Depth. 



Recent: Soil and gravel 

Alamosa formation: 

Blue clay 

Black sand (first flow) . . . 

Blue clay 

Black sand (second flow) 

Blue clay 

Red sand (third flow). . . 

Blue clay.. ., 

Red sand (fourth flow).. 

Blue clay 

Red sand (fifth flow) 

Blue clay 

Red sand (sixth flow) 

Blue clay 

Red sand (seventh flow) . 

Blue clay 

Red sand (heavy flow). . 

Blue clay 

Red sand (ninth flow)... 

Blue clay 

Red sand (tenth flow) 

Blue clay 

Gravel (eleventh flow) . . 

Clay 

Sand (twelfth flow) 



Feet. 
30 

15 

1 
19 

3 
17 

2 
16 

2 
15 

2 
10 

2 
11 

1 
14 

3 
17 

3 
10 

3 

3 

17 
12 

5 



Feet. 



30 

45 

46 

65 

68 

85 

87 

103 

105 

120 

122 

132 

134 

145 

146 

160 

163 

180 

183 

193 

196 

199 

216 

228 

233 



64 



THE SAN LUIS VALLEY, COLORADO. 



The ninth flow has a head of 12 feet, which formerly was 16 or 18 
feet; the tenth flow has a head of 15 feet. 

The well of the La Jara Milling and Elevator Company has a depth 
of 308 feet, a diameter of 4 J inches, and a temperature of 48°. An 
analysis of the water from this well may be found in the table of 
analyses, page 112. 

The well at the residence of L. A. Norland is 4 J inches in diameter 
and 325 feet in depth, cased to 300 feet. The temperature is 49£°. 



"+- 



Center sec. 14 




300 600 900 FEET 



Figure 5. — Plat ol La Jara, showing location of wells. 

Reduced to 3 inches it throws a jet 18 inches high; reduced to 2 inches 
it throws a jet 7 feet high. The jet for the full aperture of the well 
is about 3 inches. 

On the ranch of William Lambert, 1 mile north and 1 mile west 
of La Jara, a well 210 feet in depth gives this section: 



FLOWING WELLS. 
Section of Lambert well. 



65 



Recent: Gravel and sand 
Alamoea formation: 

Clay 

Sand (first flow) 

Clay 

Sand (second flow).. 

Clay 

Sand (third flow) 

Clay 

Solid rock below. 



Thick- 
ness. 


Depth. 


Feet. 


Feet. 


18 


18 


109 


. 127 


1 


126 


19 


' 147 


1 


148 


39 


' 187 


1 


188 


22 


210 



This well is not included in the series extending eastward 
from Capulin, as described on page 95, because the water was 
struck in the water-bearing beds of the basin and not in the lava, 
as in those wells. Furthermore, it is possible, though not probable, 



Sections 
II*. , ,12 



14 



'A 



Vz Mile 



Figure 6. — Plat of Richfield, showing location of wells. 

that the rock struck in this particular well may have been a large 
bowlder. 

The plat of the village of Richfield (fig. 6), half a mile northeast 
of La Jara, shows the location and number of wells in that place. 

42120°— wsp 240—10 5 



66 



THE SAN LUIS VALLEY, COLOKADO. 



SANFORD AND VICINITY. 



A plat of the town of Sanford, which covers H sections, is shown 
in figure 7. The blocks are 220 yards from street to street, and each 
block in the more closely settled portions of the town contains from 
one to four wells. Most of these are shallow, ranging in depth from 



Sections 

jsuy?_. 



.9] 



4 



• 


• • 


• 








• 1 




• • 
• 








• 




• 








• 
• 




• 

• • 








• • 

• 

• • 




• • 

• • 








*. 


* 
• 








• • 

• 


• 
• 


• 






-# 



r 



Vz 



Sections 
2onzi 



. 1 1. || g [_! 

» » • • 



3 






■#■ 

IMile 
i 



Figure 7.— Plat of Sanford, showing location of wells. 

70 to 200 feet, and nearly all are 2 inches in diameter. Many wells 
which formerly obtained the first flow at 70 feet have since had to 
be sunk deeper, owing to the exhaustion of the first flow by mutual 
interference of the wells, which number 126 in the village. > The 
following section is given as typical of these wells: 



FLOWING WELLS. 
Characteristic well section at Sanford. 



67 



Thick- 
ness. 



Depth. 



22 
34 

70 
72 
95 
97 
110 
112 
123 
126 
145 
146 
165 
166 
185 
187 



Recent: 

Soil and gravel 

Sand 

Alamosa formation: 

BJue clay 

Black sand (first flow) . . 

Blue clay 

Red sand (second flow) . 

Blue clay 

Red sand (third flow). . . 

Blue clay 

Red sand (fourth flow).. 

Blue clay 

Red sand (fifth flow) 

Blue clay 

Red sand (sixth flow). . . 

Blue clay 

Red sand (seventh flow) 



Feet. 
22 
12 

36 

2 
23 

2 
13 

2 
11 

3 
19 

1 
19 

1 
19 

2 



VICINITY OF LOS SAUCES. 

The little Mexican plaza, Los Sauces, lies a mile or so south of the 
artesian limit, but a number of wells on the Atkinson, Austin, Stewart, 
Myers, Becker, and Hansen ranches lie nearer to Los Sauces than to 
any other post-office in the valley. 

On the Peter Hansen ranch there are a number of 2 and 3 inch 
wells which have good flows. The depth ranges from 200 to 300 feet, 
and the water has a temperature of 53° to 55°. 

On Fritz Becker's ranch a well in the NE. { sec. 15, T. 36 N., R. 11 
E., flows about 26 gallons a minute. It has the following section: 

Section of Becker well. 



Thick- 
ness. 



Depth. 



Alamosa formation: 

Sand and clay 

Hard streak 

Sand (flow) 

Clay with hard streaks 
Sarid (flow) 



Feet. 

39 

1 

1 

127 

1 



Feet. 
39 
40 
41 
168 
169 



On W. H. Myers's lower ranch on Trinchera Creek, 4 miles above 
the mouth of the creek, near the eastern limit of flowing wells, six 
wells have been sunk which have yielded small flows. One of these 
near the house, 300 feet deep, had the following section: 

Section of Myers well. 



Thick- 
ness. 



Depth. 



Recent: 

Soil and sand 

Gravel 

Alamosa formation: 

Clay 

Clay and sand 

Fine gravel (small flow) 

Clay and sand (no further flow) 



Feet. 



16 
2 

40 

82 

5 

155 



16 
18 

58 
140 
145 
300 



68 



THE SAN LUIS VALLEY, COLOEADO. 



On the Stewart ranch, opposite the mouth of Trinchera Creek, 
several 3-inch wells, 170 to 300 feet deep, have good flows and are 
utilized in irrigating hay land. 

On the Austin ranch, at the mouth of the Conejos, are a number of 
2, 3, and 4 inch wells which have unexpectedly small flows, consider- 
ing that they are at the very lowest point in the artesian basin. It 
has been already shown that this small flow is in all probability due 
to the escape of the water from the artesian water beds into the gravel 
beds of the Santa Fe formation. 

On the Atkinson ranch, in the NW. I sec. 9, T. 35 N., R. 11 E., 
there are several 2-inch wells from 125 to 140 feet deep. Three of 
these wells were sunk at a total cost, exclusive of casing, of $35. One 
of them has a flow of 65 gallons. The first flow, a small one, was 
reached at a depth of 33 feet. 



PARMA AND VICINITY. 



The big well on the Parma' Land Company's farm, in the southeast 
corner of sec. 14, T. 38 N., R. 8 E., a mile west of Parma station, has 
the following section: 

Section of Parma Land Company's well. 



Recent: 

Soil 

Coarse gravel 

Fine gravel , 

Sand 

Alamosa formation: 

Blue clay 

Sand 

Clay 

Fine sand (first flow, weak) 

Clay 

Sand 

Clay 

Coarse sand and gravel 

Clay 

Gravel 

Clay 

Sand (flow) 

Clay 

Sand (small flow) 

Clay 

Sand 

Clay 

Sand (small flow) 

Clay 

Sand and clay 

Clay 

Sand (fair flow) 

Clay 

Sand (fair flow) 

Clay 

Sand (good flow) 

Clay, with some dry sand . . 

Sand (heavy flow) 



Thick- 
ness. 



Feet. 
3 

32 
5 
10 

20 
2 

73 
3 

17 
1 
8 
4 
8 
2 
8 
1 

23 
1 

30 
1 

16 
1 

31 
4 

18 
3 

68 
2 

26 
4 

47 
4 



Depth. 



Feet. 



3 
35 

40 
50 

70 
72 
145 
148 
165 
166 
174 
178 
186 
188 
196 
197 
220 
221 
251 
252 
268 
269 
300 
304 
322 
325 
393 
395 
421 
425 
472 
476 



This well is 6 inches in diameter and the flow rises about 1 i inches 
above the casing. 

A well in the northeast corner of sec. 34, on the same ranch and in 
the same township as the well just described, obtained flows at depths 
of 140, 225, 275, and 324 feet. 



FLOWING WELLS. 69 

A well at the residence of J. B. Outcault, in the southwest corner of 
the SE. i sec. 7, T. 38 N., R. 9 E., has flows at 180, 225, 250, 280, and 
300 feet. 

A well in the northwest corner of sec. 17, one-half mile due east of 
the Outcault well, struck big flows also at 400 and 550 feet. All 
told, this well is reported to have had about ten different flows. When 
new it had a jet 8 inches high, which is now reduced to 2£ inches. 
X At H. H. Johansen's ranch, in the NW. J SW. J sec. 24, T. 38 N., 
R. 9 E., there are two wells with good flows. The larger well, in the 
reservoir south of the house, is 813 feet deep and is cased throughout. 
The diameter is 3 inches and the flow rises 4 inches over the casing, 
indicating a flow of more than 100 gallons a minute. Flows were 
struck at 250, 500, 600, 760, and 813 feet. At the bottom rock was 
struck which could not be penetrated in half a day's drilling. 

MONTE VISTA AND VICINITY. 

A plat of the town of Monte Vista is shown in figure 8. The wells 
in Monte Vista are more closely crowded than in any other town in 
the valley, there being 225 in the town and the immediate environs. 
These are for the most part 2-inch wells, ranging in depth from 115 
to 300 feet. Many wells originally sunk to the first flow at 110 
feet have been sunk deeper to secure a better flow. At first, here as 
elsewhere in the valley, wells were cased into the first bed of clay a 
short distance. Through the caving in of numbers of these wells, 
there has been such an interchange and mingling of water between 
the different flows that toward the center of the town, in the region 
of greatest crowding of the wells, there has resulted a uniformity of 
flow and a uniformity of temperature as well. In this territory wells 
yield a flow of about 2 gallons per minute, and have a temperature of 
49°, whether the well be 130 or 300 feet deep. Around the borders 
of the town, particularly at the eastern border, wells have normal 
flows and temperatures. 

The largest well in Monte Vista is that at the Monte Vista Milling 
Company's plant, sunk in 1897. This well is 302 feet deep. It is 
cased for 106 feet with 6-inch casing, for 160 feet with 4|-inch casing, 
and for 302 feet with 3-inch casing. A section of the well is as follows : 

Section of Monte Vista Milling Company's well. » 



Thick- 
ness. 



Depth. 



Recent: 

Soil and gravelly loam 

Gravel and sand 

Alamosa formation: 

Clay 

Sand (first flow) 

Sand and gravel, with various flows. 

Coarse gravel below (strong flow). 



Feet. 
10 
50 

40 

9 

193 



Feet 
10 

60 

100 
109 
302 



70 



THE SAN LUIS VALLEY, COLORADO. 




FLOWING WELLS. 71 

The well has a pressure of about 5 pounds and a temperature of 49° 
and flows 400 gallons a minute. An analysis of the water will be 
found in the table of analyses on page 112. 

A section reported as typical for the wells in town is as follows : 

Typical section of wells in Monte Vista. 



Recent: Soil and gravel 

Alamosa formation: 

Clay 

Quicksand 

Blue clay 

Dark sand (first flow) 

Blue clay 

Dark sand (second flow) 

Blue clay 

Black sand (third flow) 

Blue clay 

Black sand (fourth flow) 

Yellow clay 

Yellow sand (fifth flow) 

Yellow clay 

Yellow sand (sixth flow) 

Yellow clay, with water-bearing beds of sand 2 feet thick at intervals of 10 to 20 feet. 
Bowlders below. 



Thick- 
ness. 



Feet. 
50 

1 
10 
50 

9 

8 

6 
10 

4 
10 

3 
14 

2 
23 

4 



Depth. 



Feet. 
50 

51 
61 
111 
120 
128 
134 
144 
148 
158 
161 
175 
177 
197 
201 
300 



All wells on the east side of town show more clay and less sand 
and gravel. The head of the first well sunk in Monte Vista is re- 
ported to have been 12 to 14 feet. By 1889, according to Professor 
Carpenter, it had fallen to 7 feet. In 1890, when the number of 
wells in Monte Vista was 88, it had fallen to 4 feet. In 1904 some 
of the deeper wells in town still had a head of 7 feet, and the mill 
well, as noted, has a head of about 1 1 feet. 

Four miles south of Monte Vista, in the valley of Rock Creek, the 
wells are very close together. The valley of Rock Creek is largely 
given over to' meadows of native hay, and the wells are designed 
to irrigate the higher portions of these meadows out of the reach of 
the ditch water. With few exceptions these wells are 2 inches in 
diameter, as are also the wells in the town of Monte Vista. North 
and northeast of Monte Vista, across the Rio Grande, in T. 39 N., 
R. 8 E., practically every quarter section has a 2-inch well for do- 
mestic use. This township is well supplied with ditch water and no 
wells have been bored for irrigation exclusively. The wells in the 
Monte Vista district, outside of the town itself, all have excellent 
flows, ranging from 6 or 8 gallons up to 30 gallons a minute. 



CENTER AND VICINITY. 



The village of Center is situated in the midst of the grain belt of 
the valley, in a region well supplied with ditch water, and the wells 
are almost exclusively bored for domestic purposes. They are ordi- 
narily 2 inches in diameter, and a fine flow is reached at about 200 to 



72 



THE SAN LUIS VALLEY, COLOEADO. 



_ Section 33 
Middle W. side 




Sections 
32J 1' |_33 






Figure 9.— Plat of Center, showing location of wells. 



FLOWING WELLS. 



73 



225 feet. The plat (fig. 9) shows the number and location of the 
wells in the village. . The following section is given as characteristic 
for wells in the immediate vicinity of the village: 

Characteristic section of wells in vicinity of Center. 



Thick- 
ness. 



Depth. 



Recent: Soil and gravel 

Alamosa formation: 

Clay and sand 

Sand (small flow, with some sulphur) 

Clay 

Sand (second flow) 

Clay 

Sand (third flow) 

Clay 

Sand (fourth flow) 



Feet. 
60 

95 

1 
10 

2 
12 

4 
12 

4 



155 
156 
166 
168 
180 
184 
196 
200 



These flows farther east are found at somewhat greater depths, 
averaging 10 feet deeper to the mile. 

A well in the SE. \ sec. 30, T. 40 N., K. 8 E., 5 miles west of south 
of Center, near the margin of the flowing-well area, is 464 feet deep. 
The first 200 feet was sand and gravel, with a little clay at the 
bottom, beneath which was obtained the first flow. Thence to the 
bottom of the well the formation was sand and gravel with some 
very thin beds of clay at intervals, but no further flow was found. 



LOCKETT AND VICINITY. 



The well on the John D. Hess place, in the southwest corner of the 
NW. \ sec. 26, T. 41 N., R. 9 E., is reported to have the following 
section : 

Section of Hess well. 



Thick- 
ness. 



Depth. 



Recent: Surface soil and gravel... 
Alamosa formation: 

Blue clay 

Blue clay with streaks of sand 

Sand 

Light-blue clay 

Sand (flow with 4-inch jet). . . 

Streaks of clay and sand 

Light-blue clay 

Sand (flow with 7-inch jet) 

Light-blue clay 

Sand (small flow) 



Feet. 
100 

120 
160 

1 



94 

150 
3 

58 

1 



Feet. 
100 

220 
380 
381 
461 
463 
557 
707 
710 
768 
769 



The well has a diameter of 3 inches and is cased for 478 feet, 
flow is estimated at 135 gallons a minute. 



The 



THE SAN LUIS VALLEY, COLORADO. 

Two miles west of south of the Hess well, in the NE. J sec. 3, T. 41 
N., R. 9 E., on H. J. Johnston's place, a well 800 feet deep has the 
following section: 

Section of Johnston well. 





Thick- 
ness. 


Depth. 


Recent: Surface gravel and sand 


Feet. 

70 

390 
2 

138 
10 

190 
5 


Feet. 

7 

460 
462 


Alamosa formation: 

Blue clay 


Sand (first flow) • 


Blue clay, with streaks of sand (flows every 15 to 30 feet) 


Sand (big flow) 


610 


Clay, with a few small streaks of sand (some small flows) 


Coarse gravel (good flow) 


SO'5 





The temperature of this well is 63°. The flow is about 150 gallons 
a minute. The water is caught in a reservoir and used for irrigation. 

VETERAN NEIGHBORHOOD. 

The territory about Veteran schoolhouse, between Veteran and Car- 
nero post-office, is one in which ditch water is likely to fail in a dry 
year, and this has led to the extensive development of artesian wells. 
This fact is brought out on the map by the close alignment of the 
wells along the west side of the farms. The strongest flows in the 
valley, considering the depth, are to be found in this neighborhood. 

One of the largest wells is the Espinosa well in the NW. J sec. 7, 
T. 42 N., R. 8 E. This well is 3 inches in diameter, 265 feet deep, and 
cased to the bottom. It throws a j et 25 inches above the top of the cas- 
ing, equivalent to a flow of over 250 gallons a minute. In 1891 it had 
a jet 33 1 inches high, as recorded by Professor Carpenter, who reports 
that it is said to have had originally a j et 4 1 inches high. The tempera- 
ture of this well is 54°. A view of the well is shown in Plate XI, A. 

A half mile north, on the Navin ranch, in the southwest corner of 
sec. 1, T. 42 N., R. 8 E., two 3-inch wells, 383 feet deep, and cased for 
83 feet, have jets 10 and 27 inches high, the well with the higher jet 
having been recently put down. The pressure of the older well as 
shown by gage indicates a head of 24 feet. The temperature is 55°. 
The combined flow of the two wells is very nearly 1 second-foot. 
The first flow was struck at 60 feet, the second at 120, and the third 
at 335 feet. A view of the newer well is shown in Plate XI, B. 

Two miles northeast of Veteran schoolhouse, in the southwest 
corner of the SE. £ sec. 31, T. 43 N., R. 8 E., the Woodhouse well, 2 
inches in diameter, has a jet of 13 inches. In this well a species of 
algae had grown in such a manner as to constrict the opening and 
cause the water to jet to a height of 4 feet. 

Practically all the wells in this region have excellent flows, but up 
the rise toward Carnero post-office the flows are smaller and smaller 
to the limit of the flowing wells. 



U. S. GEOLOGICAL SURVEY 



WATER-SUPPLY PAPER 240 PLATE XI 




A. ESPINOSA WELL, BORED IN 1 




B. NAVIN WELL, BORED IN 1903. 



FLOWING WELLS. 



15 



SWEDE CORNERS AND VICINITY. 

Over a small area in the vicinity of Swede Corners the wells have 
an unduly high temperature, out of all proportion to their depth. In 
four wells at Swede Corners, 100 to 159 feet deep, the temperatures 
range from 56° to 61°. The high temperatures extend 2 miles south- 
ward, and m the northwest corner of sec. 19, T. 43 N., R. 8 E., a well 
220 feet deep has a temperature of 58^°. A quarter mile south the 
well temperature drops to 53°, and a quarter mile southwest of that it 
is 45°, which is normal in the valley for a well 100 feet deep. One- 
half mile northeast of the Corners the temperature is 58° and 54°, but 
a mile and a half northeast it drops to 45° for a well 126 feet deep. 
Due eastward the temperatures resume the normal at about the same 
rate. No reason is apparent for these excessive temperatures except 
the probability of more recent uncooled lavas at no great distance 
below. Igneous rocks project above the valley slope 2 miles west and 
also 3 miles north of the Corners. It seems probable that there is in 
this vicinity an intrusive sheet of lava of small extent a short distance 
below the surface, the heat radiating from which raises the tempera- 
tures in the affected area. 

A 3-inch well in the NW. { SW. \ sec. 7, T. 43 N., R. 8 E., is reported 
to have this section: 

Section of well south of Swede Corners. 



Thick- 
ness. 



Depth. 



Recent: Gravel 

Alamosa formation: 

White clay 

Blue clay 

Sand (first flow) 

Blue clay 

Sand and gravel (strong flow) 



Feet. 
10 

70 
32 

1 
34 

9 



112 
113 
147 
156 



The well has a flow of about 130 gallons per minute. The tem- 
perature is 61°. 

In the northwest corner of the SE. \ sec. 6, half a mile north- 
east of the Corners, a well is reported with this section: 

Section of well northeast of Swede Corners. 



Thick- 
ness. 



Depth. 



Recent: Soil and gravel 

Alamosa formation: 

Clay 

Sand (first flow) 

Clay 

Sand (second flow) 

Clay 

Gravel ( third flow) 

Hard layer (fourth flow) 



Ft. in. 
12 



Feet. 



122 
123 
100 
101 
180 
189 
189 



76 THE SAN LUIS VALLEY, COLORADO. 

The well is 2 inches in diameter and the flow rises 3 inches above 
the casing. The temperature is 58°. 

In lot 1, in the northeast corner of the same section as the last- 
described well, there is a 3-inch well, whose water has a pronounced 
chalybeate taste and leaves a yellowish rusty deposit on the sides of 
the stream running away from the well. 

WARNER NEIGHBORHOOD. 

In the neighborhood of Warner schoolhouse the supply of water 
from the irrigation canals has been inadequate for several seasons, 
and the dependence is almost altogether on artesian water. Most 
of the wells sunk for irrigation purposes are 3 inches in diameter, 
but recently several 4, 5, and 6 inch wells have been put down for 
that purpose. These secure good flows at an average depth of about 
200 feet. The following section is given by local well drillers as 
typical of the region: 

Section of well near Warner schoolhouse. 



Thick- 
ness. 



Depth. 



Recent: 

Soil and alluvium 

Wash gravel and sand 

Alaniosa formation: 

Clay 

Sand, gravel, and clay (several small flows and one strong one) . 



Feet. 
5 
75 



100 
40 



Feet. 
5 



180 
220 



MOFFAT AND VICINITY. 

All the wells in the low ground about Moffat and extending north 
toward Mirage station have good flows ranging from 50 to 100 
gallons or more a minute. The sketch plan of the village of Moffat 
(fig. 10) shows the location and number of the wells in that place. 

The Denver and Rio Grande Railroad well at Moffat is one of the 
deepest wells in the valley. No geologic record of the well is avail- 
able. It is 1,045 feet deep. The bore is 8 inches for 300 feet, and 3 
inches from that depth to the bottom. The first flow was struck 
at 365 feet, the fourth and largest flow at 880 feet, and the sixth flow 
at a depth somewhat greater than 1,000 feet. The large flow was 
cased off, so that only the lower flow is now running. This has a 
head of over 30 feet and discharges about 207 gallons a minute into 
the water tank 27 feet above the ground. Small pecten-like shells an 
inch in diameter are reported at a depth of 900 feet. An analysis 
of water from this well will be found in the table of analyses on 
page 112. 



FLOWING WELLS. 



77 



J 



Along the course of the Rito Alto from Moffat to the flowing- 
well limit there are a number of good wells, principally on the 
Shellabarger, Wales, and Frazee ranches. A 2-inch well in the 
northeast corner of sec. 4, 2 miles northeast of Moffat, is 300 feet deep, 
cased for 200 feet. It has a flow of about 70 gallons a minute. The 
well has a head of over 32 feet. In sec. 34, half a mile northeast of 
the last-mentioned well, a 3-inch well, 770 feet deep and cased to 660 

feet, has a good 
flow. A 3 -inch 
well a short dis- 
tance northeast, 
with a depth of 
308 feet, has a flow 
which rises 3 
inches over the 
casing. 

At A. Shella- 
barger's house 
there is a well 665 
feet deep, which is 
cased 3 inches in diameter to a depth of 300 feet and 2 inches in 
diameter to a depth of 616 feet. Much difficulty was experienced in 
sinking this well, owing to the cobblestones that lay scattered all the 
way through the sand and clay. It was necessary to attach a per- 
forated pointed steel shoe to the bottom of the casing in order to 
force it down. A section of the well is as follows: 



* 1 

_l I 1 T I 1 I n 

1 • 



Figure 10. — Plat of Moffat, showing location of wells. 



Section of Shellabarger well. 



Thick- 
ness. 



Depth. 



Clay and sand with cobblestones 

White clay 

Sand (good flow) 

Clay 

Sand (flow) 

Sand and clay (flows about every 20 feet) 

Clay 

Gravel below (strong flow). 



300 

1 

2 

37 

! 
274 
24 



Feet. 
300 
301 
303 
340 
342 
616 
640 



The water has a temperature of 61°. A 2-inch well near by, 
which draws from the flow at 300 feet, now yields 8 or 10 gallons 
per minute with a head of 4 feet. Originally the head was 11 feet 
and the flow about 30 gallons a minute. The temperature is 51°. 

At the Frazee house, near the center of sec. 14, a well 367 feet deep 
has a temperature of 53°. Flows were struck at 220, 260, and 335 
feet in depth, the first two being light. 



78 THE SAN LUIS VALLEY, COLORADO. 

MIRAGE AND VICINITY. 

Mirage is situated just on the limit of the flowing-well area, 
and a number of wells which once flowed now lack a few feet of 
rising to the surface. South and west of the town the wells get good 
flows. A 3-inch well on the Davidson ranch, in the SE. I sec. 4, a 
half mile south of the post-office, has a flow of 25 gallons a minute. 
Flows were struck at 120, 155, 185, and 213 feet in depth. 

Another well on the Davidson ranch, in the NE. \ sec. 3, three- 
quarters of a mile east of the post-office, is 613 feet deep, cased to 
400 feet. No water was struck that would flow. At 613 feet water 
rose within 6 inches of the surface. Solid rock, believed to be sand- 
stone by the driller, was found at 613 feet. 

A well near the middle of the south side of the SW. \ sec. 34 was 
originally a flowing well, but the water now stands 6 feet from 
the top. 

The well at Tobler's, in the northeast corner of the SE. \ sec. 33, is 
218 feet deep. When sunk six years ago it flowed, but the water is 
now reported to stand 16 feet from the surface. Other attempts to 
get water at Tobler's show sand and clay to a depth of 200 feet, 
where there is a layer of hardpan, thence gravel to 500 feet, below 
which there is 40 feet of clay. 

A well near the northeast corner of sec. 33 is 435 feet deep. A 
flow was struck at 308 feet which yielded one-third gallon a minute 
for some time, but the flow failed and the water now stands 6 feet 
from the surface. 

A Well in the northeast corner of the SE. \ sec. 30 struck water at 
200 feet in solid gravel. In the northwest corner of the NE. \ sec. 30 
a well over 600 feet deep is 6 inches in diameter for 100 feet, thence 4 
inches for 400 feet, and 3 inches to the bottom. This well flowed a 
little originally but now lacks a few feet of rising to the surface. 

The fluctuations in the head of these wells are not to be considered 
as changes in the artesian pressure of the region but rather as local 
manifestations due to defects in the casing, caving in, or something 
of that sort. The absence of any regularity in the depth at which 
the flows are obtained is a result of the different conditions of deposi- 
tion of the sand and clay beds in the narrowed area of the valley in 
this vicinity, the sedimentation here partaking more of the character 
of the irregular deposition in alluvial fans and cones. This feature is 
likely to be more marked farther north up this arm of the valley. 

SAN ISABEL AND VICINITY. 

In the vicinity of San Isabel post-office there are a number of good 
wells. A 3-inch well in the NW. J NW. \ sec. 15, T. 43 N., R. 10 E., 
has a depth of 380 feet and a flow of 55 gallons a minute. The water 
has a temperature of 55J°, is clear and tasteless, and yields no gas, 



FLOWING WELLS. 79 

though it is near the northern limit of the Mosca-Hooper area of gas- 
bearing waters. At the post-office a 3-inch well affords a large flow 
of water with a temperature of 57°. 

In the NW. \ sec. 12, a mile northeast of the post-office, a 3-inch 
well 450 fee^t deep is cased to 200 feet. It has a head of over 30 feet, 
and a flow which rises 4 inches over the casing, yielding about 100 
gallons a minute. It is situated in a reservoir and is used in irrigation. 

In the SE. \ NE. \ sec. 2, in the same township as the well just 
described, a 3-inch well 375 feet deep has a temperature of 58° and 
affords a fair flow of water. A quarter mile south of this well a new 
3-inch well 890 feet deep affords a fine flow of water. 

On the H. Nash ranch, in the SE. \ NE. J sec. 7, T. 43 N., R. 11 E., 
just north of the Baca grant, a 3-inch well reaches a depth of 865 
feet, cased for 520 feet. Three flows were struck, the lowest of 
which is reported to jet the water 6 inches above the casing, indicat- 
ing a yield of 125 gallons a minute. A section of this well is as 

follows : 

Section of Nash well. 



Thick- 
ness. 



Depth. 



Recent: Gravel and red sand 

Alamosa formation: 

Yellow clay 

Red sand 

Yellow clay 

Red sand 

Black sand 

Blue clay 

Red and white sand (flow, 1-inch jet). 

Blue clay 

Hard white sand (flow, 3-inch jet) 

Blue clay, hard 

White sand (flow, 6-inch jet) 



Feet. 
85 

15 
30 
70 
70 

100 

150 
85 

100 
30 

100 
30 



Feet. 
85 

100 
130 
200 
270 
370 
520 
605 
705 
735 
835 
865 



The total cost of the well was 

BACA GRANT. 

The eastern limit of the flowing-well area passes through the Baca 
grant, taking in a strip on the west side of the grant in which flowing 
wells can be got, widening from 3 miles on the north to over 5 miles 
on the south. The ranch is given over to stock raising, with some 
native-hay land; so most of the wells have been sunk to obtain 
stock water. Several deep wells that failed to get water are described 
under the head of nonflowing wells in the vicinity of Crestone (p. 100). 

The well at the sheds is 3 inches in diameter and 481 feet deep. 
It flows 8 to 10 gallons a minute and has a temperature of 62°. 
The well by the lake in the southwestern portion of the grant is 3 
inches in diameter, with a flow of 25 gallons a minute. The water 
is very slightly tinted and there is a good flow of gas. At the South 
Camp the 3-inch well has a temperature of 47° and a flow of 8 gallons 
a minute. 



80 



THE SAN LUIS VALLEY, COLOEADO. 



MEDANO RANCH. 

On the Medano ranch there are twenty-seven 2 and 3 inch wells 
ranging from 200 to 600 feet in depth. The flows in general are good. 
Those on the west side of the ranch usually have more or less gas, 
and the water shows a slight brownish tint, in common with the 
waters of the Mosca-Hooper district. 

One of these, in the SE. \ sec. 7, T. 40 N., R. 12 E., known as the 
Baker well, is 476 feet deep. It is cased for some distance with 2- 
inch pipe, and to the bottom with lj-inch pipe. Small flows were 
struck at 121, 165, and 476 feet. The well went through coarse 
sand much the greater part of the distance, and there was but a small 
amount of clay. 

CALKINS RANCH. 

On Mrs. A. M. Calkins's ranch near the center of sec. 1, T. 38 N., 
R. 12 E., of three wells 217 to 228 feet deep, two struck flowing water 
and one, the easternmost, failed to get a flow. In the two wells 
water was struck at 160 feet and lacked 2 feet of reaching the sur- 
face. The flow was struck at 228 feet. 

A well on the same ranch in the SE. \ sec. 2, T. 38 N., R. 12 E., 
gave the following record : 

Section of Calkins well. 



Thick- 
ness. 



Depth. 



Recent: Gravel and sand 

Alamosa formation: 

Clay 

Black sand (water rose just to surface) 

Clay 

Black sand (second flow) 

Clay 

Black sand (strong flow) 



Feet. 
50 

10 
70 
SO 
60 
50 
10 



60 
130 
180 
240 
290 
300 



A 2-inch well 195 feet deep in sec. 16, T. 38 N., R. 12 E., bored 
in 1902, is reported to have thrown a jet 12 inches above the casing 
when new and not to have failed any since. A section of the well 
is reported as follows : 

Section of well in sec. 16, T. 38 N., R. 12 E. 



Recent: Gravel (cased) 

Alamosa formation: 

Blue clay 

Gravel size of pigeon's egg (strong flow) 



Thick- 
ness. 



Feet. 
95 



100 

1 



Depth. 



195 
196 



FLOWING WELLS. 81 

CENTRAL OR MOSCA-HOOPER REGION. 
OCCURRENCE OF GAS AND COLORED WATER. 

Lying in the trough of the valley and stretching from a point 4 
miles northeast of Alamosa within 3 miles of Moffat, with a length of 
30 miles an4 an average width of 8 miles, is an area in which gas is 
mingled with the waters of the deeper wells. Coinciding with this 
area, but extending 3 or 4 miles farther west, is a region in which the 
water of the deeper wells is colored. This color varies from the 
lightest tints of brown or brownish yellow to a decided brownish 
color, like that of swamp water or water that has collected in 
rotten wood. Both areas are shown on the map accompanying this 
report (PI. I). This region of tinted and gas-bearing water is gen- 
erally known as the Mosca-Hooper district. 

In explanation of this occurrence of gas and tinted water there is 
to be noted the significant position of the area in the trough of the 
valley, with which it so strikingly corresponds in outline. Just as 
this is now the lowest portion of the valley, it probably was so in the 
later stages of deposition of the Alamosa formation. The occurrence, 
particularly in this district, of wood, bark, peaty moss, and seeds has 
already been noted. The high content of alkalies in the tinted 
waters is shown in the table of analyses on page 112. That this is 
not a separate basin, and that the same aquifers which farther west 
yield the usual pure water of the valley here yield the tinted alkali 
and gas-bearing water, is proved by the continuity of the aquifers, 
the evidence of which has already been shown (p. 44). Consideration 
of these facts leads to the conclusion that there were arid periods 
during the deposition of the water-bearing sands and clays of the 
Alamosa formation, when the water of the lake shrank to a small 
shallow area in the trough of the valley, and that this area of more or 
less alkaline water afforded a growth of vegetation, in particular of 
mosslike plants. Later, when the deposition of the series was com- 
plete, these interbedded alkaline and peaty sands and clays became 
water bearing. As water was drawn from the area pure water from 
the outside took its place and in turn dissolved the alkalies and took 
up the peaty infusion. Thus in time, with, the continual draft upon 
the waters of the area, they must tend to become fresher and less 
highly colored and eventually, in the remote future, to become like 
the other water of the valley. The extension of the colored-water 
area beyond the gas-bearing area, west of Mosca and Hooper, admits 
of an interesting speculation. It seems reasonable that the heavy 
drain upon the water-bearing series in the region of closely crowded 
wells west of Mosca and Hooper has caused a movement of the 
waters out from the Mosca-Hooper district toward the region of heavy 
drain, and that this movement carried the colored water beyond its 

42120°— wsp 240—10 6 



82 THE SAN LUIS VALLEY, COLOEADO. 

original bounds. Just why there was not a similar migration of the 
gas is not so clear, though it is true that the gas occupying the local 
irregularities in the upper surface of the aquifers would not be so 
subject to lateral movement as the water. Furthermore, it is prob- 
able that some of the gas is stored in lenses of sand inclosed in the 
clay beds and not laterally connected with the aquifers. In such a 
situation it would not be subject to movement like that of the water. 
The presence of gas has led to some prospecting for oil. The log 
of the deepest well sunk by the Chicago and San Luis Oil Company, 
4 \ miles due east of Mosca, is given on page 43. Oil scum on the 
water and oil on the drill rope are reported from this well, but no 
flow of oil was struck, and prospecting is at a standstill. In general 
it is not to be expected that oil and gas will be struck in an artesian 
basin; yet the Florence (Colorado) oil field is an instance of such a 
relation. The oil there arises from carbonaceous shales and is stored 
in lenticular bodies of sandstone inclosed on all sides by shale. From 
the sections and discussions in the preceding pages it is clear that the 
Alamosa formation is made up of a series of persistent clay and sand 
beds, so that the occurrence of lenticular beds of sand near the center 
of the valley is not to be expected. It may be, however, that in the 
local heavy beds of clay reported in the region there are sand lenses; 
and the possibility of gas occurring in these has already been men- 
tioned. It may safely be predicted, however, that no considerable 
quantity of oil will ever be found in the Alamosa formation, for the 
beds of that formation are but slightly carbonaceous and the quan- 
tity of gas already discovered is as great a volume of hydrocarbons as 
the carbonaceous content of the formation could reasonably be 
expected to furnish. Further, the underlying Santa Fe formation 
(gravel beds interbedded with lava flows) offers very little prospect 
for oil below the Alamosa formation. The chance in the San Luis 
Valley of striking any oil-bearing beds of greater age than these at 
any depth, however great, is exceedingly remote. 

MOSCA AND VICINITY. 

No accurate log exists of any deep well in the immediate vicinity 
of Mosca, but the geologic section of the "oil well," 1,283 feet deep, 
4^ miles east of Mosca, has been given on page 43. In the village 
itself there are 17 wells, the location of which is shown on the town 
plat (fig. 11). 

The town well in Mosca is 400 feet deep. The first flow, at 160 feet, 
just comes to the surface. This flow is clear. Other flows, every 15 
to 30 feet down to a depth of 400 feet, are colored with various tints 
of light brown. The chemical composition of the water is given in 
the table of analyses, page 112. 



FLOWING WELLS. 



83 



A 5-inch well near the schoolhouse in Mosca is 500 feet deep. The 
temperature is 66° and the flow is about 50 gallons a minute. The 
water is of a decided brownish color and has a slight taste, neither 
acid nor salty, yet repellent. 

The Mosca Milling and Elevator Company's well is 4 inches in 
diameter ajad 600 feet deep. The first flow was struck at 200 feet 
and other flows about every 50 feet down to the bottom of the 
well. The well furnishes a large flow of water, which has a very 
slight brownish tint and a very small amount of gas. The tempera- 





• 



NOTE. 



Figures 11 and 12 should be transposed, 
and that on page 86 a plat of Mosca. 

Water-Supply Paper 240. 



The plat on page 83 is a plat of Hooper 



I Center 
_J ] lSec.32 
--? 



-fe- 



Figure 11.— Plat of Mosca, showing location of wells. 

ture is 69°. An analysis of the water will be found in the table of 
analyses, page 112. 

A well in the SE. \ sec, 16, a mile south of Mosca, is 385 feet deep. 
The water has a temperature of 60°, a light-brownish tint, and a 
slight taste of sulphur. This is the second flow, but the first flow, at 
80 feet, is reported to be good clear water. 

At Peter Andersen's, in the NW. \ SW. \ sec. 26, T. 39 JST., R. 10 E., 
the well is cased 2 inches in diameter to a depth of 340 feet and 1^ 



84 



THE SAN LUIS VALLEY, COLOEADO 



inches in diameter to a depth of 500 feet, the first flow, at 200 feet, 
thus being cased off. The upper flow, from a depth of 340 feet, has a 
temperature of 62° and the lower flow, from a depth of 500 feet, a 
temperature of 63°. There is probably a greater difference than this 
in the real temperatures of the flows, but flowing alongside each other 
to the surface they tend to come to an average. The upper flow has 
a perceptible color and a peculiar taste, such as one would expect of 
water standing in a hollow stump. The lower flow has a pronounced 
taste and color, and there is perceptible a very small amount of gas. 
The upper flow yields about 1 gallon and the lower about 4 gallons a 
minute. An analysis of the water from the lower flow is given in the 
table of analyses on page 112. 

A 3-inch well in the NE. \ sec. 27, one-fourth mile northwest of An- 
dersen's well, of unknown depth, has a temperature of 66°. The 
water from this well is very dark and kills all the vegetation along the 
overflow from the well in a strip 10 to 15 feet wide. Over this area 
white crusts of alkali have formed around the drying edges of the 
stream. 

A mile south of Andersen's well, in the northwest corner of the 
SW. \ sec. 35, a 2-inch well, 500 feet deep, which has now ceased to 
flow, furnished water for the analysis by Dr. W. P. Headden, which is 
given in the table of analyses on page 112. 

In the NW. \ NW. \ sec. 8, T. 38 N., R. 11 E., there is a 3-inch well 
800 feet deep which flows 3 inches over the casing, indicating a flow 
of about 90 gallons a minute. The temperature is 71°. There is a 
slight flow of gas. The water has a light-yellowish tint and a slight 
taste of sulphur. Its chemical composition is indicated in the table 
of analyses, page 112. 

Several miles west of Mosca, on the J. M. Chritton ranch, the fol- 
lowing section occurs, according to Professor Carpenter: 

Section of Chritton well. 



Thick- 
ness. 



Depth. 



Recent: 

Dark sandy loam 

Coarse sand and gravel 

Alamosa formation: 

Fine light-yellow sand 

Yellow impervious clay . . . 

Blue clay 

Black sand (small flow) . . . 

Blue clay 

Fine black sand (fine flow) 

Blue clay 

Fine black sand (flow) 

Blue clay 

Black sand (strong flow). 



Feet. 
7 
13 

22 
18 
98 
1 
4 
3 
45 
12 
53 



Feel. 



7 
20 

42 
60 
158 
159 
163 
166 
211 
223 
276 



Plowing wells. 



85 



On the Watson ranch, 5 miles northwest of Mosca, there are two 
3-inch wells which are both 712 feet deep and are cased to a depth of 
200 feet. One of them is in the SW. | sec. 35, and the other is in the 
SE. i sec.^34, T. 40 N., R. 9 E. The flow of these wells has a tem- 
perature of 63° and forms a jet 5£ inches high, indicating a flow of 
approximately 120 gallons a minute. A section of this well is 
reported as follows: 

Section of Watson well. 



Thick- 
ness. 



Depth. 



Eecent: Gravel and sand 

Alamosa formation: 

Yellow clay 

Gray sand 

Blue clay 

Black sand (water, no flow) 

Blue clay 

Sand (first flow, small) 

Blue clay 

Sand (second flow) : 

Blue clay 

Sand (third flow) 

Clay with sand beds (numerous flows) 

Sand (main flow) 

Clay with sand beds (small flows) 



Feet. 
60 

4 
16 
30 

3 
87 

2 
38 

2 
58 

2 

333 

12 

65 



Feet. 



GO 



110 
113 

200 
202 
240 
242 
300 
31)2 
635 
647 
712 



HOOPER AND VICINITY. 



There are 23 wells shown on the Hooper town plat (fig. 12). Most 
of these flow through the drill rods, consisting of 1-inch pipes, which 
are allowed to remain in the wells in order to lessen the liability to 
cave in that is shown by wells in this vicinity. 

The Garrison Mill and Elevator Company's well was sunk in 
August, 1897, has a diameter of 4^ inches, is cased to the bottom, 
and flows 70 gallons a minute. The temperature is 69°. The water 
has a pronounced taste of soda and a slight brownish tint, with a 
very small flow of gas. An analysis of the water will be found in 
the table of analyses on page 112. The log. is as follows: 

Log of Garrison Mill and Elevator Company well. 



Thick- 
ness. 



Depth. 



Recent : Surface gravel and sand 

Alamosa formation: 

Blue clay 

Black sand (no flow) 

Blue clay 

Fine sand (first flow, small) 

Blue clay with 2-foot beds of sand and flows every 50 feet (various flows) 

Blue clay, in strata 15-30 feet thick, with interstratified sand beds 12 feet thick 
(various flows) 



Feet. 
90 

15 
5 

90 

5 

445 

90 



Feet. 



90 

105 
110 

200 
205 
650 



86 



THE SAN LUIS VALLEY, COLORADO. 



The Denver and Rio Grande Railroad well, situated 250 feet south- 
east of that described above, has the following record : 

Log of Denver and Rio Grande Railroad well at Hooper. 



Recent: 

Soil 

Gravel 

Alamosa formation: 

Sand 

Blue clay 

Blue clay with sand strata 

Sand (small flow) 

Clay and sand (various flows) . 

Blue clay 

Sand below (heavy flow). 



Thick- 
ness. 


Depth. 


Feet. 


Feet. 


3 


3 


10 


13 


52 


65 


143 


208 


124 


332 


1 


333 


251 


584 


30 


614 



The diameter of the well is 4 inches. The flow originally had a 
head 27 feet above the top of the ground and the well had a flow of 




Sections 

iiThb 



400 800 1200 FEET 



Figure 12. — Plat of Hooper, showing location of wells. 

50 gallons a minute. The water has a decided brownish tint and 
is without gas. An analysis of the water is given in the table of 
analyses on page 112. 



FLOWING WELLS. 87 

The town well, situated in the intersection of Fourth avenue and 
Main street, is about 300 feet deep. It is cased for a short distance 
with 3-inch casing, and inside this is a 2-inch casing reaching to the 
bottom of tke well. The flow is approximately 1 gallon a minute 
but was originally about 4 gallons. The temperature is 53°. The 
water is clear, with a slight taste of sulphur. The sodium carbonate 
in this well, as determined by the electrolytic method, is 103 parts 
per million. 

A well in block 8, in the northeast corner of the town, is 1 inch in 
diameter and 425 feet deep. It has a head somewhat more than 14 
feet. The temperature is 54° and the water clear. 

A 2-inch well in the northwest corner of sec. 6, T. 42 N., R. 10 E., 
has a temperature of 65° and flows 2\ inches above the casing, indi- 
cating a volume of 35 gallons a minute. The water has a decided 
brownish tint. An analysis of this water, published by the United 
States Department of Agriculture,® is given in the table of analyses 
on page 112. 

A well one-half mile west of Swede schoolhouse, in the SE. \ sec. 
19, T. 41 N., R. 10 E., struck flows at the following depths: 

Feet. 

First flow 220 

Second flow (good) 380 

Third flow 450 

Fourth flow 510 

Fifth flow 550 

The well is cased for 112 feet. The flows below 380 feet are now 
shut off by caved walls. The temperature is 59° and the well has 
a flow of 15 gallons a minute. The water has a slight brownish 
tint. 

In the corral on the ranch of George W. Clark, in the SE. \ NW. \ 
sec. 18, T. 41 N., R. 11 E., there is a 3-inch well 630 feet deep, cased 
to 360 feet. It has a temperature of 60° and a discharge of about 
70 gallons a minute. The water has a faint brownish tint and is 
highly charged with gas. The well is equipped with a device for 
separating the gas from the water and storing it, a reproduction in 
miniature of a municipal gas-storage tank, which is shown in Plate 
XII, A. Collected in this way the well affords a sufficient volume 
of gas for a cook stove and one gas jet. The gas, in common with 

a Field operations, Bureau of Soils, 1903, p. 1114. 



88 THE SAN LUIS VALLEY, COLORADO. 

that of the Mosca-Hooper district, has a strong benzine-like odor. 
The section of the well is as follows : 

Section of Clark gas well. 



Material. 



Thick- 
ness. 



Depth. 



Recent (in part): Sand and gravel 

Alamosa formation: 

Clay 

Sand (first flow, small) 

Clay 

Sand (second flow) 

Clay 

Sand (flow with gas) 

Clay and sand (flows with gas every 20 to 30 feet) . 

Clay 

Very hard stratum 

Sand (strong flow of water with gas) 



Feet. 
185 

15 

50 

25 

10 

30 

10 

252 

50 

(a) 

3 



Feet. 
185 

200 
250 
275 
285 
315 
325 
577 
627 
627 
630 



On the Star ranch, in sec. 26, T. 42 N., R. 10 E., there are two 
3-inch wells, both of which yield gas. The one at the corral, sup- 
posed to be between 400 and 500 feet deep, has a temperature of 
48° and flows less than a gallon a minute. The water is of a light- 
yellow color. The escaping gas forms a frothy foam, which stands 6 
inches above the surface of the water and burns with a bright yel- 
low flame. Half a mile southeast of the corral is the other well, 
bored 3 inches in diameter to a depth of 400 feet and 2 inches in 
diameter to a depth of 800 feet. The water has a temperature of 
70°, a light-brownish tint, and a peculiar saltish taste. The flow of 
water, mixed with gas, fills the 2-inch horizontal discharge pipe and 
amounts to 20 or 25 gallons a minute. It is used for stock water. 
The well affords a considerable volume of gas, which burns with a 
yellow flame 2 feet high. The amount of gas would apparently be 
ample to run a heating or cooking stove or several gas jets. 



KINNEY RANCH. 



On the Stephen Kinney ranch there are ten wells, ranging from 500 
to 1,018 feet deep, all of which have, for the valley, copious flows of 
gas though not very good flows of water. Owing to the tendency 
of 2 and 3 inch wells to become choked up by indrawn chunks of 
clay, the drill rods were left in all these wells, so that the water now 
flows through 1-inch pipes. An unusual feature of the geologic 
structure of this region is the reported preponderance of clay, the 
scarcity and small size of the sand beds, and the great depths to the 
flows. 

The house well, near the center of sec. 35, T. 43 N., R. 10 E., is 
cased 2 inches in diameter for 454 feet, shutting off the first flow, a 
small one with much gas, at 450 feet. The 1-inch casing reaches to 



•J. S. GEOLOGICAL SURVEY 



WATER-SUPPLY PAPER 240 PLATE XII 




A. CLARK'S GAS WELL AND STORAGE TANK. 




B. HUNT SPRINGS, LOOKING EASTWARD ACROSS THE NORTH END OF SAN LUIS VALLEY. 



FLOWING WELLS. 89 

630 feet and the depth of the well is 639 feet. The flow is about 10 
gallons a minute, with much gas. The water has a temperature of 
,63° and a taste and tint similar to the other gas-bearing waters of the 
Mosca-Hooper district. A short distance from this well another one 
has been recently sunk with the object of obtaining gas for domestic 
uses. The diameter is 2 inches and the depth 766 feet. The tem- 
perature of the water is 68°. A good flow of gas was obtained, which 
is collected and stored in a suitable tank. 

In the SW. \ sec. 3, T. 42 N., R. 10 E., there is a well cased3 inches 
to 864 feet and 2 inches to 995 feet. The total depth of the well is 
1,018 feet. The well stopped in a black sticky mud, which could not 
be handled by the hydraulic process of boring. A small flow was 
found at 600 feet and a better one at 700 feet, but both had so much 
gas that they choked up the pipes. According to the driller, Mr. 
Charles Speiser, the gas here caused a geyser-like intermittent flow, 
which, at intervals of an hour, caused the water to flow to the top of 
the derrick, 32 feet high. Later the interval lengthened to four or 
six hours, and mud and water were thrown to a height of 60 and 75 
feet. The rise and fall of the column was gradual. White at first 
with the foam of included gas, the column would afterward become 
black with indrawn mud and sand. When the foam was ignited at 
the bottom the flame would run to the top of the column and fire balls 
would drop down the side and reignite the foam at the bottom, the 
flame mounting the column again. After a month the well became 
choked. It was cleaned out and the gas was cased off. Another 
flow was found at 760 feet, which again threw mud and water over 
the derrick. After the escape of the gas a soft sandy mud filled with 
"seeds" was pumped out. The "seeds" floated upon the water and 
covered it. They were soft and were brownish in color, turning to 
black in sunlight. This flow was likewise cased off, and but a single 
weak flow, at 830 feet, was found to the bottom of the well. This well 
is but 8 miles southeast of the Denver and Rio Grande Railroad well at 
Moffat, which is nearly of the same depth and which struck such 
large flows of water. 

Another well in the southwest corner of sec. 11, T. 42 N., R. 10 E., 
is 835 feet deep. No flow at all was noticed in drilling this well, but 
a small one with considerable gas came in afterward. The flow of 
water is irregular, sometimes very small, sometimes spouting (mixed 
with gas) 4 feet over the casing, and again flowing gas only. 

JACOBS RANCH. 

The Jacobs ranch marks the extreme northwestern extent of the gas 
region. Several wells yield considerable gas, but no use is made of it. 

In the NW. | sec. 26, T. 43 N., R. 9 E., a 2-inch well 500 feet deep 
is cased for 125 feet. It has a flow of 25 gallons a minute. The 



90 



THE SAN LUIS VALLEY, COLORADO. 



water has a temperature of 58° and the usual taste of the gas-bearing 

water, but no color is visible. There is a fair flow of gas. 

At the ranch house, in the NE. \. sec. 34, the 3-inch well is 404 feet 

deep and is cased for 224 feet. It flows about 40 gallons a minute. 

The water has a temperature of 57°, a slight taste, and a faint color. 

It has also a good flow of gas. 

The strongest flow of gas on the ranch, however, is found in the 

NE. I sec. 10, T. 42 N., R. 9 E., in a 3-inch well 650 feet deep, cased 

for 325 feet. The flow of water 
is reported to be about 70 gallons 
per minute. 



• Flowing well 
oNon-flowing well 




SAN LUIS VILLAGE. 

San Luis village lies altogether 
outside of the artesian area of 
the valley. Culebra Creek cuts 
through the lava-capped San Pe- 
dro Mesa and east of the mesa, 
together with the Rito Seco, it 
has cut out of the Santa Fe forma- 
tion a parklike valley 3 miles 
wide and several miles long. 
Situated on the Rito Seco, just 
above the point where it joins 
Culebra Creek at the gap in the 
mesa, is the village of San Luis, 
a plat of the older portion of 
which is shown in figure 13. 
Within the town limits in the 
last few years a number of wells 
have been bored winch yield flow- 
ing water. In a few other wells 
the water comes almost to the 
surface. In two wells of this 
sort, where the water rises within 
6 or 8 inches of the surface, a hole 
3 or 4 feet deep has been dug 
about the mouth of the well and the casing cut off low enough 
to give a flow of a gallon or so per minute. The waste water escapes 
into the gravel and causes no inconvenience. The distribution of 
the wells and their depth are shown in figure 13. The flowing 
wells are bunched about the court-house square but extend a little 
farther to the south; outside of this area the wells either do not strike 
water or yield water that does not rise to the surface. In this area 
of flowing wells there seem to be two flows, one at a depth of about 20 



Figure 13.— Plat of San Luis, showing location of 
wells. 



FLOWING WELLS. 91 

feet and another at 50 to 60 feet. Most of the wells draw from the 
upper flow. Of those deep enough to reach the lower flow one at least 
draws from fne upper flow. Judging from the small size of the arte- 
sian area, its shallowness, and the irregularity of the formations, as 
seen hi the well sections, the flow is probably due to underflow of the 
Rito Seco, and its localization to irregularity of deposits in some pre- 
historic channel of that stream. The temperature (in December) 
ranges from 45° to 47° but bears no relation to the depth of the well, 
depending rather on the rate of flow of the well; the weaker wells 
have the lower temperature because the water in its slow rise through 
the ground has opportunity to cool to surface-soil temperatures. 

The court-house well, bored in 1892, is 3 inches in diameter and 58 
feet deep, cased all the way. The flow was struck at 25 feet, under a 
few inches of clay, and the well was continued in gravel to the bottom 
without increasing the flow. The temperature is 46°. 

Doctor Smith made two unsuccessful attempts to find water just 
west of the court-house, across Main street. The deepest hole gives 
the following section: 

Section of Smith well. 



Thick- 
ness. 



Depth. 



Alluvial clay. 

Sand 

Hard clay 

Red sand with streaks of blue sand (no flow). 



Feet. 

15 

5 

1 

179 



Feet. 

15 

20 

21 

200 



The water sank as fast as it was pumped into the well in drilling. 
Another well near by, 70 feet deep, also failed to get water. A 
third well was sunk in the court-house yard and struck a small flow 
at 20 feet and a better one, yielding 5 gallons a minute, at 59 feet. 
This is the same flow that the court-house well strikes. 

W. S. Parrish bored a third well in the court-house yard, south of the 
other two. This is only 30 feet deep, but it evidently reaches the 
same flow as the others; for when it is allowed to flow freely, its orifice 
being lower than those of the other two, their flow is completely 
stopped. This difficulty is remedied by reducing the discharge pipe 
of the Parrish well to one-half inch; then the others are affected but 
little. The water is piped to Mr. Parrish's house, near the southwest 
corner of the town. 

Five wells in a row along Main street south of the courthouse yard 
are 22 to 32 feet deep and have flows varying from 1 to 5 gallons a 
minute. The temperature of the shallow ones is 47°. In the 
blocks immediately east and southeast of the court-house three wells 
are 30 to 36 feet deep, the flow ranging from 1 to 2 gallons a minute 
and the temperature from 45° to 47 



ITO 



92 



THE SAN LUIS VALLEY, COLORADO. 



East and west of the schoolhouse and church the wells do not flow, 
the water lacking from 6 inches to 5 feet of reaching the surface. 

South of the village, in the neighborhood of the mill, Mr. Parrish 
made several attempts to strike flowing water but failed in each 
attempt, though the elevation is about 20 feet less than that of 
the court-house yard. The deepest well, 197 feet deep, furnishes; 
this section: 

Log of Parrish' s mill well. 



Thick- 
ness. 



Depth. 



Soil 

Gravel 

Quicksand and streaks of clay 
Hard sand 



Feet. 

4 

23 

75 

95 



Feet. 

4 

27 

102 

197 



The water rose within 3 feet of the surface. Another well was 
sunk to a depth of 80 feet at a point 300 yards northeast of the mill, 
in the vicinity of several springs. This showed a section similar 
to that just given. Above a depth of 40 feet the water rose within 2 
feet of the surface, but as boring progressed below that depth the 
water sank instead of rising. 

A well in the bottom, 1 mile southeast of the village, went 60 feet 
in bowlders, and one in the gap one-half mile west of the village 
went 25 feet in bowlders with no water. 

NONFLOWTNG WELLS. 

ANTONITO. 

Plate III, A, shows a view looking west from the vicinity of 
Antonito at the eastward-sloping lava-capped mesa about Los 
Mogotes Peak. The lava sheet can be seen to approach the level of 
the valley bottom and merge with it. This lava sheet is reached in 
various wells near Antonito. The town well reaches a depth of 400 
feet. The first 235 feet is a cribbed shaft measuring 3 by 5 feet. In 
the bottom of this shaft a hole was bored 165 feet farther. A geo- 
logic section of the well, as reported by Mr. E. L. Myers, is as follows: 

Section of Antonito city well. 



Thick- 
ness. 



Depth- 



Recent: Loose gravel and soil 

Santa Fe formation: 

Solid lava 

Lava ash 

Gravel 

Coarse bowlders 

Gravel and sand becoming finer 

Conglomerate cement 

Gravel and sand 

Gravel and sand (bored) 



Feet. 
35 

22 
10 
25 
35 
96 
3 



57 
67 
92 
127 
223 
226 
235 
400 



NONFLOWING WELLS. 



93 



From this well there is pumped weekly 70,000 gallons of water, 
being the whole supply of the town for domestic purposes. A 
gasoline engin-e lifts the water 250 feet into a 35,000-gallon tank. 
The water is cold, tasteless, and hard. 

The Denver and Rio Grande Railroad well is about 350 feet from 
the town well. The log of this well is as follows : 

Log of Denver and Rio Grande Railroad well at Antonito. 



Thick- 
ness. 



Depth. 



Recent: Gravel and bowlders 
Santa Fe formation: 

Solid lava 

Lime cement 

Clay and bowlders 

Marl 

Cemented gravel 

Marl 

Cemented gravel 

Marl 

Cemented gravel (water) . 

Loose gravel 

Cemented gravel 

Loose gravel 



Feet. 

m 

35 

14 
55" 
18 
13 
17 
20 

8 
20 

1 
13 

2 



Feet. 



73*. 

75 
130 
148 
161 
178 
198 
206 
226 
227 
240 
242 



The water rises in this well 16 feet. With two hours' hard pump- 
ing the water is lowered to 2 feet, after which 4,000 gallons per hour 
can be taken out without affecting the water level. The analysis of 
this water is given in the table of analyses, page 112. The high per- 
centage of this water in CaC0 2 (whence its hardness) is noticeable, 
being exceeded in this respect only by the water from the Valley View 
Hot Springs, so far as the waters of the valley have been analyzed. 



MANASSA AND VICINITY. 

Manassa lies just south of the southernmost limit of flowing wells. 
Sharp little lava hills rise out of the valley half a mile south and 
2 miles east of the town. Several attempts to obtain flowing water 
have been made within the limits of the town and in the vicinity. A 
well 125 feet deep in the northeast portion of the town went through 
bowlders. The water is reported to rise within 3 feet of the surface. 
A well in the schoolhouse yard, said to be 74 feet deep, struck water, 
which rises within 12 feet of the top. 



94 



THE SAF LUIS VALLEY, COLOEADO. 



During the winter of 1903-4 the State bored an experimental 
well in the schoolhouse yard. The log of this well, as furnished by 
the state engineer of Colorado, is as follows : 

Record of state well, at Manassa. 



Recent: Sand and bowlders 

Alamosa formation: 

Clay 

Clay and sand 

Blue clay 

Sand 

Fine sand 

Coarse sand 

Coarse sand and fine gravel 

Fine light sand 

Coarse sand 

Santa Fe formation (?): 

Lava bowlders 

Dark sand and clay 

Fine clay sand 

Coarse sand 

Coarse sand and bowlders . . 

Fine clay sand 

Red lava sand 

Lava cobblestones 

Clay and sand 

Fine black sand; some clay 

Volcanic ash (sand) 



Thick- 
ness. 



Feet. 

77 



Depth. 



Feet. 



77 

84 
89 
92 
154 
168 
189 
200 
210 
280 

285 
296 
305 
334 
339 
342 
360 
380 
435 
450 
512 



It is evident from the preponderance of sand and gravel in this well 
that Manassa lies at the extreme edge of the alternating series of 
clays and sands which hold the artesian water under pressure, and 
that southwest of the town the clays will be found to be replaced 
altogether by sands and gravels. In that region water can not be 
found under sufficient pressure to reach the surface but will rise in 
the wells simply to the height of the general water level of the region 
or the undergrpund water table. 

Water was found through the entire depth of the well below the 
first 6 feet, except in strata of clay. The water rises within 26 feet 
of the surface of the ground. The well is 10 inches in diameter for 
the first 342 feet, and below that 8 inches in diameter. 

A well on the Braiden ranch, in the SW. \ sec. 20,T.34 N., R. 10 E., 
is 133 feet deep with a rock bottom. The water rises within 3 feet of 
the surface. 

The McDaniell place, in the northwest corner of sec. 33, T. 34 N., 
R. 10 E., has a well 33 feet deep, in which the water rises within 7 
feet of the surface. The section of the well is as follows: 

Record of McDaniell well. 



Thick- 
ness. 



Depth. 



Recent: 

Soil, gravel, and clay . 
Gravel 

Lava below. 



Feet. 



NONFLOWING WELLS. 



95 



Two miles northwest of Manassa, in the NW. \ sec. 10, T. 34 N., 
R. 9 E., a prospect well was sunk by the Conejos County Oil Com- 
pany to a cjepth of 318 feet. This well is about 1J miles from the 
edge of the flowing-well area and about 30 feet higher. The record 
of the well, kindly furnished by Mr. W. O. Meier, is as follows: 

Record of Conejos County Oil Company's well. 



Thick- 
ness. 



Depth. 



Recent: Gravel and sand 

Alamosa formation: 

Blue clay 

Black sand (first flow, rose to —1 foot) 

Gravel, sand , and clay 

Santa Fe formation: 

Lava 

Very red granular rock 

White sand (probably pumice) 

Black sand (water rose to —20 feet) . . . 



Feet. 
70 



12 

8 
155 



70 

82 
90 
245 

275 

295 
300 
304 



CAPTJLIN AND VICINITY. 



The wells in the vicinity of Capulin are dug wells. The usual depth 
is 30 feet, at which point they strike lava. A basin is made in the 
lava, into which the water percolates from the gravel. 

North of Capulin the Knapp well is reported to show this section: 

Section of Knapp well. 



Eecent: 

Gravel and bowlders 

Hard stratum, not rock . . 
Sand (drill rods dropped) 
Bowlders 



Thick- 
ness. 



Depth. 



Feet. 
200 
202 
234 
250 



The water rose in the well about 100 feet, that is, within 150 feet 
of the surface. This well is far up on the alluvial slope, as indicated 
by the great excess of gravel and bowlders. 

East of Capulin and between that place and the Harvey ranch there 
are several deep wells. A mile and a half east of the village, 500 
yards south of the center of sec. 10, T. 35 N., R. 8 E., several wells on 
the Palmer ranch reach lava at 64 and 66 feet, and afford a more 
permanent supply of water than the surface wells, 25 feet deep, which 
go dry in winter. 



96 THE SAN LUIS VALLEY, COLORADO. 

On the George S. Lovett place, in the SW. J NE. \ sec. 11, a mile 
east of the well last described, a well gave this section: 

Section of Lovett well. 



Thick- 
ness. 



Depth. 



Recent: Bowlders.. 
Alamosa formation: 

Sand 

Blue clay 



Feet. 
55 



Feet, 
55 



115 
175 



Water was struck at 65 feet and rose within 5 feet of the surface. 
At L. D. Eskridge's place, in the northwest corner of sec. 18, T. 35 
N., R. 9 E., a well shows this section: 

Section of Eskridge well. 



Thick- 
ness. 



Depth. 



Recent and Alamosa formation: Sand and clay. 
Santa Fe formation: Lava 



Feet. 
150 
101J 



Feet 
150 
2511 



The water rises within 26 feet of the surface. 

At S. E. Newcombe's, half a mile due east of the Eskridge well, two 
wells struck lava at 180 feet, and one of them penetrated it a depth 
of 20 feet. In the house well the water stands 10 feet from the 
surface, and in the barn well it rises within 3 feet of the surface. 

At the schoolhouse, a quarter of a mile northeast of Newcombe's, 
the rock was struck at 185 feet and the water rises within 8 feet of 
the surface. 

Joe Fred's well, in the SE. \ sec. 31, T. 36 N., R. 9 E., gives this 

section: 

Section of Fred well. 



Recent: Gra"vel 

Alamosa formation: Clay 
Rock below. 



Thick- 
ness. 



Feet. 

45 

315 



Depth. 



Feet. 
45 
360 



The water rose within 8 feet of the surface. 

On the Harvey ranch a well in the SW. \ sec. 5, T. 35 N., R. 9 E., 
is 265 feet deep, with a flow between 10 and 12 gallons a minute. 
There was a small flow just over the rock, but the present supply 
comes from crevices in the rock, into which the well is cased for 
so^ne distance. There fs some uncertainty as to the depth at which 



NONFLOWING WELLS. 97 

rock was reached, but apparently it was about 232 feet, at which 
point, according to the state engineer's report, the first flow was 
obtained.** From the same source it is learned that the original flow 
was reported to be 100 gallons a minute. On the same ranch there 
are two other wells which reach rock, one at the house and another 
at the barn. The former is 6 inches in diameter to rock, which was 
reached at about 195 feet. There was a small flow here, but the bore, 
reduced to 4 inches, was continued to a depth of 229 feet. This well 
has a flow of several gallons a minute. The well at the barn, north- 
east of the house, is 265 feet deep, reaching the rock at about 220 
feet. This well also has a flow of several gallons a minute, and 
originally the water rose from it 8 feet above the surface. 

These wells on the Harvey ranch, though flowing wells, are described 
here because they form a continuous series with the other wells just 
described, which struck rock but did not get flowing water. It is 
apparent from the difference in depth at which rock is reached in the 
Joe Fred well and in the others that irregularities exist in the surface 
of the bed-rock lava. Possibly the northeastward limit of the upper 
lava flow lies between the Harvey wells and the Fred well. So far 
as is known to the writer, bed rock has not been struck in any well 
north and east of that point, except at the Lambert well, 1 mile north- 
west of La Jara, described on page 65. 

The Eskridge and Newcombe wells are artesian, though nonflowing, 
but the Knapp, Palmer, and Lovett wells merely penetrate the under- 
ground water table, which is probably higher near La Jara and 
Alamosa creeks than it is at a distance from them. 

BOWEN SCHOOL AND VICINITY. 

Two miles southwest of Bowen school, in the northwest corner of 

the SW. i sec. 33, T. 37 N., R. 8 E., a well 240 feet deep gives this 

section : 

Section of well in sec. 33, T.37 N.,R.8 E. 



Recent: Gravel and bowlders . 
Alamosa formation: 

Hard clay 

Sand (water) 

Clay 

Gravel below. 



Thick- 
ness. 



Feet. 
60 



Depth. 



Feet. 
60 

140 
141 
240 



This well is nearly 2 miles outside of the limits of flowing wells, 
and the water lacks 40 feet of rising to the top of the well. 

aRept. State Engineer of Colorado for 1889-90, p. 339. 
42120°— wsp 240—10 7 



98 THE SAN LUIS VALLEY, COLORADO. 

Two miles east of north of Bowen, in the northeast corner of the 
NW. \ sec. 11, T. 36 N., R. 8 E., a well passed through 60 feet of 
gravel and 160 feet of clay ; striking water in gravel. The water rises 
within 14 feet of the surface. 

Four miles west of Bowen, on the Gunbarrel road, in the northwest 
corner of sec. 31, T. 37 N., R. 8 E., the Strauss dug well is 70 feet 
deep in sand and gravel. It is well up toward the apex of the Cat 
Creek alluvial cone, and in the wet season (about June) it fills to the 
top. In the fall and winter it goes nearly dry, demonstrating an 
annual variation of about 70 feet in the ground-water level in this 
part of the alluvial slope. The well is about 150 feet higher than the 
rim of the flowing-well area. 

MONTE VISTA AND VICINITY. 

From Monte Vista to Alamosa Creek the Monte Vista canal is 
approximately parallel with the margin of the flowing-well area, 
and about a mile from it. As the Monte Vista canal is practically the 
upper limit of settlement in the valley, except along inflowing streams, 
there are few wells outside of the canal, but between the canal and 
the flowing-well margin there are many nonflowing wells that pene- 
trate the artesian water-bearing beds. 

Two miles west of Monte Vista, in the NE. \ NE. \ sec. 34, T. 39 
N., R. 7 E., on the second terrace of the Rio Grande, the water lacks 
18 feet of rising to the surface. One mile south, in the NE. \ sec. 3, 
T. 38 N., R. 7 E., a well 125 feet deep failed to get any water what- 
ever. In the southeast quarter of the same section two bore holes, 
66 and 76 feet deep, struck water which failed to rise. They are 
reported to strike rock, but more probably they struck bowlders. 

DEL NORTE. 

The municipal water supply of Del Norte is pumped from the Rio 
Grande into a small reservoir in the side of a small hill just south of 
the town, from which it is distributed. Wells in town strike the 
underflow of the Rio Grande at short distances, furnishing a plentiful 
supply of wholesome water. 

In 1 890 an artesian well was bored at the intersection of two of the 
main streets of the town, reaching a depth of 450 feet. A very small 
flow of water was obtained, at first a stream not larger than a lead 
pencil, which afterward strengthened to a flow of 2 gallons a minute. 
The water is reported to rise from beneath a sheet of lava, though 
details of the geologic record of the well are not available. The water 
has a temperature of 54° and a decided taste of soda. No analysis is 
available. 



NONFLOWING WELLS. 99 

LA GARITA AND VICINITY. 

Wells east and south of La Garita strike water in the gravel of the 
alluvial slope. A well at the Dunn ranch, near the center of sec. 16, 
T. 41 N., R. 7 E., at 180 feet in depth, struck quicksand and water, 
which rose within 10 feet of the surface. This well is about 2 miles 
from the limit of flowing wells. To the south is the great triangular 
alluvial fan of the Rio Grande. The lower portion of the fan, adja- 
cent to the flowing-well area of the valley, affords wells in which the 
water rises under artesian pressure to a greater or less height, accord- 
ing to the distance from the flowing- well limit. But in the upper 
part, toward the apex of the fan, the clay strata of the valley thin out 
and give place to sand and gravel beds. Wells in this area will be 
bored in gravel and sand and will yield water whose level, depending 
on the general water level in that region, will be higher near the Rio 
Grande and lower at a distance from the river. 

SAGUACHE AND VICINITY. 

The limiting line of the flowing-well area crosses Saguache Creek 
3 miles below Saguache, which lies in the creek valley somewhat within 
the margin of the foothills and is surrounded by isolated lava hills. 
The chances of striking any water but the underflow of the creek 
depend upon striking gravel beds beneath the lava containing water 
under pressure. Several attempts to strike deep water have been 
made, one by the State, one by the town, and others by private citi- 
zens, but none have struck flowing water. The information recorded 
below has been kindly communicated by the Hon. J. H. Williams, 
county judge of Saguache County. 

The state well, 1 mile northwest of town, reported to be 1,100 
feet deep, struck water at about 75 feet, which rose within 12 or 14 
feet of the surface. No record is available as to geologic formations 
penetrated. The well did not succeed in getting a better flow of 
water with greater depth. 

The park well, in the public park within the town limits, is reported 
to be 665 feet deep. Water was struck at 65 feet in gravel and rose 
within 12 feet of the surface. 

The Jordan well, just .south of the town, is 180 feet deep, with the 
water level 8 feet from the surface; the Curtis well, in the eastern 
part of town, is 100 feet deep and has water at the same level. Sev- 
eral other wells in the town get water at about 65 feet, which rises 
to a level 8 or 12 feet from the surface. 

VILLA GROVE AND VICINITY. 

The village of Villa Grove is situated in the northern arm of the 
valley, which extends up the valley of San Luis Creek and the upper 
portion of which is known as Homans Park. The village lies about 



100 THE SAN LUIS VALLEY, COLORADO. 

9 miles above the upper limit of flowing wells and in all probability 
some distance also beyond the extreme limits of the sand and clay 
series in which the artesian water of the valley is found. Owing to 
the proximity of mountain highland on either side of this narrow 
tongue of the valley, the sediments consisted largely of sand, gravel, 
and bowlders without the clay strata necessary to confine the water. 
The domestic water supply is derived from shallow wells which reach 
the underflow of Kerber Creek. 

The Denver and Rio Grande Railroad in 1891 sunk a well at Villa 
Grove to a depth of 960 feet in gravel and sand with no clay. The 
water rose within 100 feet of the top. In 1899 the well was acci- 
dentally clogged, and since then it has not been in use. 

On the Pitzer ranch, about 6 miles southeast of Villa Grove and 
2 miles east of Chamberlain Hot Springs, in the NE. \ SE. \ sec. 8, 
T. 45 N., R. 10 E., a well between 300 and 400 feet deep struck water, 
which rose within 12 feet of the surface. This well probably strikes 
the artesian water of the valley, as flowing wells are obtained 3 miles 
to the south. 

CRESTONE AND VICINITY. 

The water supply of Crestone is derived from shallow wells, in the 
gravel of the alluvial slope. These wells reach the underflow of Cres- 
tone Creek, which meanders through the village, and they furnish 
an abundance of water, which, from the situation of the town just 
at the base of the mountains, is pure and cold. The danger of con- 
tamination is wholly local. 

On the Baca grant, a mile and a quarter southwest of the village, 
in the fork of North and South Crestone creeks, a bore went 410 feet 
in bowlders, with no water. A half mile farther west, at the ranch 
house, in a well 496 feet deep, the water rose to a level 6 feet below 
the surface. On Dead Man Creek a bore 1,100 feet deep was all in 
sand with no water. A mile and a half east of Antelope Springs a 
1,000-foot bore yielded no water. These wells on the grant are in 
the alluvial slope of the Sangre de Cristo Range; and as the clay 
members of the valley formation do not reach that far there is no 
confining layer to retain the water under the pressure necessary to 
yield a flow. 

BALDY STATION AND VICINITY. 

At the Willie Hansen ranch, 2 miles northwest of Baldy station, on 
the Denver and Rio Grande Railroad, a number of wells have been 
bored just about at the margin of the flowing- well area. One in the 
NE. i sec. 17, T. 37 N., R. 12 E., is 500 feet deep, reported all in sand. 
The water rises within 3 feet of the surface. A half mile clue east is 
another in which the water rises within 10 feet of the top. Two 
miles due north of Baldy station, near the middle of the north side of 



SPRINGS. 101 

sec. 10, T. 37 N., R. 12 E., a well is reported 300 feet deep, all in sand, 
in which the water lacks 8 feet of rising to the surface. Near the 
middle of the west side of sec. 36, T. 38 N., R. 12 E., a well 300 feet 
deep in sand and gravel is reported to have struck no water what- 
ever. Another well in the NE. \ sec. 24, in the same township, well 
up on the alluvial slope of the Sierra Blanca, struck no water. 
Though it is evident that the clay beds of the water-bearing series are 
replaced at about this point by sand and gravel, it is not likely 
that they terminate so abruptly. It is probable that small clay beds 
have been overlooked in the wells near the edge of the flowing-well 
area. 

FORT GARLAND AND VICINITY. 

The surface wells which furnish the domestic water supply of Fort 
Garland strike the underflow of Ute Creek. The principal danger of 
pollution lies in the pastures along the valley of the creek above the 
town. 

On the south bank of Trinchera Creek, in the SW. \ sec. 31, T. 30 S., 
R. 72 W., 4 miles southwest of Fort Garland, a well on W. H. Myers's 
ranch, 108 feet deep, struck water which rose within 18 inches of the 
surface. At Frank Beckwith's, in the southwest corner of the SE. \ 
sec. 26, T. 30 S., R. 73 W., a well in Trinchera Valley gave this section: 

Section of Beckwith well. 



Recent: 

Soil 

Smali bowlders 

Alamosa formation: Clay and sand. 



Thick- 
ness. 



Feet. 

4 

31 

118 



Depth. 



Feet. 
4 
35 
153 



The water rises within 6 feet of the top of the well. 

SPRINGS. 

The valley affords numerous springs, both large and small. These, 
with a few exceptions, emerge near the junction of the foothills and 
the valley bottom. They have mostly the normal temperatures of 
the shallow artesian waters of the valley, but two springs in the north 
end of the valley' and one near the south end have rather warm 
temperatures. 

Mclntire Springs. — The largest group of springs in the valley is 
that formerly known as Los Ojos, or commonly as Mclntire's Springs, 
on the south side of Conejos River in the northeast corner of sec. 13, 
T. 35 N., R. 10 E. These springs rise in the bottom just at the foot 
of one of the San Luis Hills, and some of the springs appear to come 
up through crevices in the lava. The group is limited to an area not 
more than 300 feet in diameter, and they all merge into one stream. 



102 THE SAN LUIS VALLEY, COLORADO. 

The flow from these springs, which is practically constant and does 
not vary with rainfall, has been measured many times and is found 
to be about 21 second-feet. The temperature of the stream com- 
prising the united flow of the springs is 60°. Some of the smaller 
springs have a temperature of 54°, but most of the individual springs 
are either just over or just under 60°. As these springs rise against 
or even through comparatively recent lava rocks, their temperature 
is not a reliable clue to the depth from which they come. A view of 
these springs looking toward the west, up the valley of Conejos River, 
is shown in Plate XIII, B. An analysis of the water is given in the 
table on page 112. 

The flow of these springs was filed upon at an early date by the 
inhabitants of the Mexican village of Los Sauces for irrigation pur- 
poses, for which its temperature makes it peculiarly valuable in the 
early season. 

Dexter Spring. — Dexter Spring is on the Austin ranch (formerly 
the Dexter tract), in the NE. \ sec. 9, T. 35 N., R. 11 E., 2 miles 
northeast of Mclntire Springs, and like those springs rises along the 
edge of the lava bench, which extends from the base of Cerro de los 
Ojitos, the northernmost of the San Luis Hills, west of the Rio 
Grande. An analysis of water from this spring is given in the table 
of analyses, page 112. The temperature is reported to be 71°. 

Other springs along Conejos River. — Other smaller springs emerge 
near the base of the San Luis Hills along Conejos River from a point 
near its mouth up to the vicinity of Manassa, as was noted on pages 17 
and 38, where the supposition was advanced that the water of these 
springs rises from the water-bearing beds of the Alamosa formation, 
where they abut against the lava of the Santa Fe formation of the 
San Luis Hills. 

Spring Creek. — Spring Creek has its head in sec. 12, T. 37 N., R. 7 
E., half a mile west of the Gunbarrel road and just under the rise of 
the steeper alluvial slope. Water rises over an area 15 by 40 feet, 
flowing more than a cubic foot a second. It is augmented by seepage 
until at the point where it crosses the Gunbarrel road it has a volume 
of several second-feet. The flow is affected by melting snows in the 
mountains. It has a temperature of 57°. 

Russell Springs. — Russell Springs are situated in the NE. J sec. 24, 
T. 43 N., R. 7 E. These springs rise in a grassy area 40 acres or so in 
extent, underlain by a peaty black mud. In this area about twenty- 
five springs display temperatures ranging from 44° to 56°. The 
temperature where the water crosses the Gunbarrel -road is about 52°. 
The water has no taste. The water from these springs drains east- 
ward 2 miles into Russell Lakes. 

Hunt Springs. — Hunt Springs are in the NE. I sec. 3, T. 44 N., 
R. 8 E., at the foot of the small lava hill 4 miles east of Saguache. 



SPRINGS. 103 

The group comprises about a dozen springs which range in tempera- 
ture from 43° to 52°. They emerge over an area about 1 acre in 
extent and nearly on a level with the valley bottom to the east, in 
which the overflow from the springs forms large marshy ponds, as 
shown in Plate XII, B. The water has no taste and forms no deposit. 

Antelope Springs. — Antelope Springs are situated near the middle 
of the south side of the Luis Maria Baca Spanish grant. They were 
not visited by the writer. 

Medano Springs. — There are two springs on the Medano ranch. 
The Big Spring is in the NW. | sec. 2, T. 40 N., R. 12 E. This spring 
emerges in a circular bed of quicksand 100 feet in diameter, lying at 
the head of a gully 15 feet deep, which reaches back into the edge of 
the great dune area. The stream where it first emerges is not large, 
but it is much increased below by seepage. The temperature of the 
stream 100 feet below the spring is 51°. The Little Spring lies 2 
miles southeast of the Big Spring, in the SW. \ sec. 12 of the same 
township, and is similar to it except in size. These springs, heading 
in the edge of the great dune area, are popularly and no doubt cor- 
rectly believed to be the reappearing waters of Mosca and Medano 
creeks, which disappear beneath the sand several miles to the east. 

Washington Springs. — Washington Springs are just north of the 
Denver and Rio Grande Railroad, in the northeast corner of sec. 14, 
T. 37 N., R. 11 E. They emerge from the base and even from the top 
of a small sand dune on the edge of the terrace which is the northern 
continuation of Hansen Bluff. Those at the base of the mound on 
the north side flow about 10 gallons a minute. Another forms a pool 
at the very top of the mound. The temperature of the water is 52°. 
The dune is covered with grass and is quite the highest point in the 
vicinity. Presumably the vegetation growing around this spring 
caught and held the drifting sand, gradually building up the mound, 
and carrying the spring up with it. On the lower ground, south of 
the railroad, in the northwest quarter of the same section, a mound 
50 yards in diameter has been similarly built up to a height of 20 feet 
or so. Several small springs emerge from the top and slopes of the 
mound. 

Chamberlain Hot Springs. — The Chamberlain Hot Springs are in 
the southeast corner of sec. 12, T. 45 N., R. 9 E., and in the SW. { 
sec. 7, T. 45 N., R. 10 E., near the station on the Denver and Rio 
Grande Railroad. East of the railroad and just south of the station, 
in sec. 12, a number of springs bubble up in a large pool about 50 feet 
in diameter. The temperature is 90° at the edge but is probably 
higher near the center, where the springs rise. Two other small 
springs, 25 and 50 yards southeast, have temperatures of 114° and 
112°, respectively. The water of the large pool has no taste and 
shows no tufaceous deposit. Several species of water bugs and an 



1'04 THE SAN LUIS VALLEY, COLOKADO. 

abundance of the plant Chara thrive in the water. The spring was 
formerly used as a swimming pool, and the water was also piped to a 
bathing house farther east. The pool, somewhat obscured by rising 
steam, is shown in Plate XIII, A. 

The springs in sec. 7 emerge from three small mounds about 50 
yards each in diameter and ranging from 20 to 35 feet in height, 
built up of laminated tufaceous sinter deposited by the springs. No 
commercial use has been made of these springs for a number of years 
and no analysis of the water is available. 

The springs of the south mound are the most active. The spring 
by the bath house has a temperature of 127°. A slight but pro- 
nounced taste of both soda and iron is evident. There is a yellowish 
precipitate in the stream flowing away from the spring, and green 
algse grow in the spring and along the stream. A pool 20 feet in 
diameter on the summit of the mound has a temperature of 72°. 
Other springs near by have temperatures ranging from 128° to 131°. 

The east mound has springs on the east and north sides with tem- 
peratures ranging from 112° to 124°. The spring on the summit of 
the mound is extinct. 

The north mound is the largest and highest of the three, being 
about 40 feet high. The springs upon this mound are now extinct, 
except a group upon a bench on the southeast edge of the mound. 
These range in temperature from 120° to 130°. 

Valley ■ View Hot Springs. — Valley View Hot Springs are in the 
SW. i sec. 31, T. 46 N., R. 10 E. They emerge from the mountain 
side a short distance above the upper limit of the alluvial slope. 
The country rock consists of quartzite. The springs are five in num- 
ber, three being situated on the north branch of the stream, one on 
the middle branch, and one, several hundred feet higher up the 
mountain side, on the south branch. The north spring has a tem- 
perature of 72°. The next spring to the south and the largest one 
of the group, over which there has been built a bath house, has a 
temperature of 95°. The third spring to the south has a tempera- 
ture of 87°. The fourth spring, the one on the middle branch, has a 
temperature of 96° and the one on the south branch a temperature 
of 99°. The analysis of the largest spring is shown in the table of 
analyses, page 112. The springs have been improved by the erection 
of a hotel, a bath house, and several cottages and afford a modest 
business as a resort. 

Hot Creek Springs. — A small stream emptying into La Jara Creek, 
near Capulin, is known as Agua Caliente, or Hot Creek. The higher 
temperature of the water in this creek, which renders it so desirable 
for purposes of irrigation in the early season, is due to hot springs 
which occur in its upper course. 



UNDEBGEOUND WATEBS. 105 

CHARACTERISTICS OF THE ARTESIAN BASIN. 
GBOUPING OF WELLS. 

A glance at the map will show that by far the greater number of 
wells in the San Luis basin are along its western slope. Various fac- 
tors have contributed to this segregation. The principal one, per- 
haps, has been the presence of greater irrigation systems on that side 
of the valley and consequent greater population; but another im- 
portant cause is the fact that the slighter inclination of the strata 
on that side of the valley has made the matter of obtaining an artesian 
flow much simpler, involving less chances of failure and less expense. 

VAEIATIONS IN FLOW. 

Seasonal variations. — Near the margin of the area of flowing wells 
there is a decided periodical variation in pressure or head. Just on 
the limiting line there are a number of wells that flow during a certain 
portion of the year and have to be pumped during the remainder of 
it. The variation in head in these wells is not accurately determined 
but is about 4 feet. The same variation affects wells within the 
limits of the flowing-well area, but it there shows itself as a slightly 
increased or decreased flow and is not so manifest as in wells along 
the critical line. These wells, with the seasonal intermissions, flow 
during the summer and fall and do not flow for the rest of the year. 
As this is the season of irrigation the flow of the wells is popularly 
said to "come up with the sub." (that is, with the rise of the water 
table due to subirrigation) ; and this is probably true, though of 
course there is no direct connection of the ditch water with the 
aquifer. The water in the water-carrying stratum is under constant 
hydrostatic pressure, tending to rise to the surface and pressing 
upward always against the confining clay bed above. Any increase 
of weight upon this clay bed is transmitted downward to the aquifer, 
which, being thus under greater pressure, yields greater flows than 
before. The water which is put upon the ground in irrigation adds 
a very definite increment to the pressure upon the aquifer and it is 
therefore true that the flow rises with the ditch water. Likewise, 
the rainfall during the showery season adds to the general pressure 
and helps to increase the head. The seasonal fluctuation due to 
irrigation is hence closely allied in principle to the tidal fluctuations 
in artesian wells at the seashore." 

Gradual failure of wells. — Several factors contribute to cause the 
gradual failure of wells. Among these one of the most obvious is the 
growth of a green alga. This lines the inside of a vertical pipe 
down for a foot or so, probably as far as light is efficacious, and by 



a For a summary of the literature relating to tidal fluctuations in artesian wells near the seacoast see 
Water-Supply Paper U. S. Geol. Survey No. 155, 1906, pp.65-69. 



106 THE SAN LUIS VALLEY, COLORADO. 

its continued growth often constricts the opening so that the water 
is forced to a height ; and the considerable pressure thus exerted on 
the well doubtless to an appreciable extent reduces its flow. 

Another possible cause of the gradual failure of wells is a reduction 
of the porosity of the sand bed through which the water conies to the 
bottom of the well. This, has been popularly expressed as a "silting 
up of the water bed." It seems more reasonable to suppose that the 
free silica, in which the analyses show the water to be especially 
high, is by the reduction of pressure at the bottom of the well in part 
precipitated about the grains of sand in the aquifer adjacent to the 
bottom of the well, which tends to seal the interstices and to reduce 
the porosity of the bed. For most of their long journey through the 
beds of granitic and volcanic sand the artesian waters are undoubt- 
edly augmenting their silica content, as shown by the fact that the 
silicic acid in water from the Rio Grande at Del Norte is 24 parts per 
million, whereas that of various wells in the San Luis Valley ranges 
from 38 to 106 parts per million. But this fact is not in any way 
inconsistent with the theory that some precipitation of silica may 
take place as the waters pass from the sands and gravels of the 
aquifer to the opening at the bottom of the well tube. Decisive 
proof of this deposition of silica would be had if secondarily enlarged 
grains of sand should be brought up in cleaning out some old well 
that had slowly failed. The writer, though repeatedly trying, has 
as yet failed to obtain such material with which to test the theory. 

But presumably the greater number of cases of gradual failure of 
wells are due to the increase in number beyond the capacity of the 
aquifer to furnish the full flow for each. The minimum distance 
from one another at which wells may be put down without affecting 
the common flow is difficult to determine and depends on the size of 
the bore, the capacity of the aquifer, and the artesian pressure. It 
has been shown that the wells in the town of Monte Vista so seriously 
affect one another that they have ordinarily a uniform flow. The 
distance there between the wells is from 50 to 200 feet. A mile north- 
west of La Jara, on William Lambert's place, of two wells 150 feet 
apart the newer well seriously affected the flow of the old well. It is 
noticed in all the towns of the valley that the flows now obtained 
are not so strong as the flows formerly obtained at the same depth, 
though the adjacent wells may not seem to be affected by the sinking 
of a new well. The normal flow of wells in towns is often so con- 
cealed by the piping or restricted by partial use only that it might be 
seriously impaired without the fact becoming apparent. Such a 
failure, of course, may be due in part to other causes, but it is 
undoubtedly due mainly to the increase of wells. It seems certain 
that the large wells may be placed as close as 440 yards, and reason- 



CHARACTERISTICS OF THE ARTESIAN BASIN. 107 

ably sure that they may be as close as 220 yards, without affecting 
one another. Smaller wells can of course be placed still closer with- 
out mutual injury. If it is desired to have two or more large wells 
close together, in order that the combined flow may be used for irri- 
gation or stored in a reservoir, they may be so placed if they are bored 
to different flows and all but the lower flow is cased off from the 
deeper well. In this way there will be no interference. Instead of 
sinking two separate wells of different depths, the same effect may be 
gained by reducing the bore of a large well and continuing it to lower 
flows, the water from the deeper flows coming up through the smaller 
inside casing. However, separate wells will in general be preferable, 
owing to the difficulty of cleaning and repairing multiple wells. 

By far the greater number of wells, as will be seen later, are cased 
only to the first solid clay, a depth varying ordinarily from 10 to 40 
or 50 feet. The bore is continued through the various water-bearing 
beds until a suitable flow is reached. As long as this deeper flow of 
higher pressure continues the water from the upper water beds will 
not come into the bore and there will be no mingling of the different 
flows; but if the well is plugged or is choked near the top, the lower 
flows, which are under greater pressure, will spread out in the upper 
beds that are under less pressure, so that the pressure tends to be 
equalized in the upper and lower flows, and as a result the pressure 
and consequently the yield of the lower flows are weakened. This 
process has taken place to such an extent toward the center of the 
town of Monte Vista that the yield from the various flows is identical, 
and likewise the temperature. 

Sudden failure of wells. — In almost all cases sudden failure is due 
to the caving away of the clay walls of the well. In a well that is not 
cased the caving in of the clay anywhere along the bore may shut off 
the water from below the caved place. In a well that is cased to the 
sand bed furnishing the flow ordinarily there is a rather large cavity 
in the sand at the bottom of the casing, resulting from the sand being 
carried up and thrown out of the well. Occasionally large pieces of 
the clay bed above may tumble into this cavity and clog the bottom 
of the casing. In the vicinity of Hooper, and northward on the Kin- 
ney ranch, the practice is to let the 1-inch pipe that serves as a drill 
rod remain in the well after completion. This rod, projecting down- 
ward below the casing and into the cavity at the base of the well, 
ordinarily prevents the complete closure of the well by any falling 
chunk of clay. 

Irregularities in flows from the same aquifer, — Adjacent wells that 
strike the same water bed may have very different flows. These 
irregularities are probably to be explained by the irregularities in 
thickness or porosity of the water-bearing bed. The rate at which 



108 THE SAN LUIS VALLEY, COLORADO. 

water passes through sand varies with the size of the sand particles, 
being greater for the coarser varieties. For this reason the gravel 
flow obtained in certain parts of the valley is a very free, strong flow. 
Local variations in the same bed of sand therefore exert a very definite 
effect upon the quantity of flow. 

As the rate of flow through sand of a given size is fixed, the volume 
of flow from any bed of sand of that size depends on the thickness of 
the bed. It is not to be presumed that the beds of sand in the valley, 
though known to be of great extent and persistence, are of the same 
thickness throughout. Any formation built up more or less in delta 
form, as are the deposits of the Rio Grande alluvial fan, must of 
necessity differ in thickness from place to place, and such differences 
are undoubtedly ample to account for any variations in flow from 
the same bed. 

VARIATION IN TEMPERATURE. 
VERTICAL VARIATION". 

The vertical range in temperature observed in the wells of the 
valley is from a minimum of 45° in shallow wells to a maximum of 75° 
for the Bucher well at Alamosa. The increase of temperature with 
depth is very regular; estimated from the deep cased wells near 
Alamosa it is 1 ° for 28£ feet. 

The minimum temperature is found in wells on the low ground 
near the Rio Grande north of Monte Vista. Southward along the 
Gunbarrel road and southeastward along the flowing-well limit to the 
vicinity of La Jara the shallowest wells have temperatures of about 
46°. Southeast of La Jara along Conejos River the shallowest wells 
have temperatures of 50° to 52°. North of Monte Vista along the 
Gunbarrel road the temperature of the first flow likewise increases 
and in the vicinity of Center it is about 51° or 52°. Farther north, 
in the Veteran neighborhood, the temperature is lower again, 46° 
and 47 ° in wells reaching the first flows. These temperatures continue 
to the vicinity of Russell Springs, but from there to Swede Corners, 
2\ miles north, there is an increase in temperature of 10° in wells of 
practically the same depth. The area of excessive temperature 
about Swede Corners has already been described (p. 75). On the 
east side of the basin the temperatures are very regular and such as 
would normally be expected, that is to say, 46° and 47° for the first 
flow. 

It is noticeable that the wells of lowest temperature on the west side 
of the valley are near the courses of the larger streams and that the 
higher temperatures are found in the interstream areas. The waters 
of these streams, derived from melting snow for a large part of the 
year, are notably cold. Daily observations at Del Norte give the 



CHARACTERISTICS OF THE ARTESIAN BASIN. 109 

following mean temperatures of the Rio Grande from July 1, 1905, 
to November 30, 1906, excluding January, February, and March, 
during which no gage readings are made: 

Monthly mean temperature, in degrees Fahrenheit, of the Rio Grande at Del Norte. 
[Richard D. Adams, United States Geological Survey, observer.] 



April 

May 

June 

July 

August 

September. 

October 

November. 
December. . 



Monthly mean 

Mean of all observations. 



1905. 



57.2 
56.6 
51.0 
40.6 
35.4 
35.8 



1906. 



37.6 
44.0 
47.5 
53.5 
56.0 
50.0 
40.5 
34.7 



46.1 I 45.5 
45.8 



It will be noted that the mean for the period of the observations 
corresponds closely to the temperature of the coldest wells, namely, 
45°. If the observations covered the remaining portion of the year, 
the winter months would doubtless lower the mean to a point below 
that of the coldest wells. Water of this mean temperature entering 
the artesian system is warmed in its passage through the aquifer and, 
rising rapidly to the surface through the wells, emerges at practically 
the temperature of the aquifer in the region of the well; but in 
acquiring this temperature it has abstracted heat from the aquifer. 
The general loss of heat by radiation from the surface of the earth is 
counterbalanced by an equivalent upward ilow of heat from the inter- 
nal supply; but in beds as nearly homogeneous as those of the arte- 
sian system this increment of heat will be uniform and evenly supplied 
over the whole area, and thus those areas from which most heat has 
been abstracted will still remain below the normal temperature. The 
different beds of the system tend then to become colder and colder, 
and the first portions to reach the ultimate limit (the mean tempera- 
ture of the river water) will be those nearer the intake — that is, along 
the larger streams. That this limit has been practically reached 
north of Monte Vista has been pointed out above. 

This local excessive cooling of the upper strata of the earth is 
apparently the explanation of the high temperature gradient of 1 ° for 
28^ feet as compared with 1° for 50 or 60 feet, the average increase 
as found in deep dry wells, shafts, and mines. 

The wells with higher temperatures about Swede Corners and along 
the lower course of the Conejos, with adjacent areas of lava, in all 
probability derive their excess of heat from subterranean bodies of 
uncooled igneous rocks. The hot springs which have been described 
seem likewise to owe their temperature to such a source. 



110 



THE SAN LUIS VALLEY, COLORADO. 



SEASONAL VARIATIONS. 



The impression obtains to some extent that the wells of the valley 
are warmer in winter than in summer. At first thought this would 
seem to be a delusion, due to the difference in air temperatures in the 
different seasons affecting the personal standard of comparison. 
However, in view of the fact that water from the streams enters the 
aquifers at all seasons of the year with varying temperatures, and 
that the draft on the wells, and consequently the rate of transmission 
of the water through the sand, is much greater in the irrigating season, 
it seems not impossible that there may be seasonal variations. A 
series of temperature readings was taken of a well in the vicinity of 
Monte Vista and of two near La Jara. 



Variation in temperature of artesian wells. 



Date (1906). 


1. 


2. 


3. 


July 16 


47.2 
47.5 
47.4 
47.4 
47.3 
47.2 
47.3 
47.3 
47.2 
47.2 
47.2 


48.8 
48.7 
48.7 
48.8 
48.8 
48.9 
48.6 
48.6 
48.4 
48.3 
48.2 










45.6 




45.8 




45.7 




45.7 


October 16 


45.8 




45.8 












45.8 







1. La Jara, Eskridge well; SE. ' sec. 15, T. 35 N., It. 35 E.; L. A. Norland, observer. 

2. La Jara, Mill well; L. A. Norland, observer. 

3. Monte Vista, SW. \ sec. 19, T. 39 N., R. 8 E.; G. M. Whitead, observer. 

These readings show that such variation as exists is measured in 
tenths of a degree. Well 1 (excluding the first reading, which is 
probably in error) shows a definite and regular decrease in tempera- 
ture in the winter. This is a 6-inch well with a small flow. The 
column of water therefore moves rather slowly up the casing, and 
there is opportunity for winter ground temperatures to affect the 
temperature of the water, which they undoubtedly do. In well 2, 
until after October 1, there was a large flow, and up to that date the 
readings are valuable. After that date the flow was so reduced that 
the slow-moving column of water in the well was affected by the 
ground temperature. Up to the time mentioned the readings indi- 
cate a slight rise in temperature. Readings taken at short intervals 
during a warm day at each of these wells showed no measurable diur- 
nal variation. Well 3, near the limit of flowing wells and the artesian 
intake from the Rio Grande, is more favorably situated to show such 
a variation than either of the other two wells. The readings seem 
to indicate a rise of two-tenths of a degree. It is regrettable that 
the observations on this well are not extensive enough to be more 
decisive. 



UNDERGROUND WATERS. Ill 

QUALITY OF THE WATER. 

In the table on page 112 there have been brought together all avail- 
able analyses of the well and spring waters of the San Luis Valley. 
They were variously expressed as grains per United States gallon, 
grains per imperial gallon, or parts per hundred thousand, but have 
been uniformly reduced to parts per million and put in terms of ions. 

The following determinations of total salts were furnished by the 
United States Department of Agriculture : 

Total salts determined by electrolysis, in well waters of San Luis Valley. 

[Bailey E. Brown, analyst.] 

Parts 
per million. 

Well, northwest corner of the NE. \ sec. 5, T. 40 N., R. 9 E 87 

Center, town well 87 

Center, hotel well 90 

Elliott well, NE. i NE. \ sec. 13, T. 40 N., R. 7 E 90 

Monte Vista, Elliott well 89 

The accuracy of the conductivity method is proportional to the 
degree of dissociation of the salts in solution. Since these waters are 
among the best waters of the valley and are in all respects similar to 
the waters at La Jara and Monte Vista, which yield by gravimetric 
methods 152 and 156 parts per million of solid matter, respectively, it 
follows that the dissociation of solutes in the valley water is far from 
complete. The discrepancy is probably to be ascribed largely to the 
notable quantity of free silica in these waters. Though not to be 
relied upon, therefore, to give a correct notion of the total solids, the 
determinations nevertheless show the relative salinity of the waters 
included and demonstrate the uniformity of quality over the area 
covered by the samples. 

The analyses in the table (p. 112) with few exceptions, have been 
made for commercial purposes, mostly with a view to determining 
the fitness of the waters for boiler use. In certain of the analyses 
credited to W. P. Headden, however, the process was carried fur- 
ther and supplementary sanitary determinations were made. The 
amounts of free ammonia and albuminoid ammonia present in two 
deep artesian wells and two springs are given in the following table : 

Ammonia in San Luis Valley waters. 
[Parts per million.] 

Albuminoid 
ammonia. 



Bucher well 0. 112 0. 034 

McNieland well .050 .006 

Mclntire Springs .100 .092 

Dexter Spring None. . 082 




112 



THE SAN LUIS VALLEY, COLORADO. 




QUALITY OP WATEK. 113 

Except in the Mosca-Hooper district, the waters of the valley are 
of a very good quality, having a maximum total solids of 240 and a 
minimum of 152 parts per million, as determined by complete analysis. 
These amounts are two to three times as great as those for the water 
of the Rio Grande at Del Norte, which contains 88.5 parts per million 
of total solids. The additional material in solution in the well waters 
is taken up by the water in its slow passage through the beds of sand 
and clay making up the water-bearing series. 

W. P. Headden a has called attention to the unusually high per- 
centage of silicic acid in the mountain waters of Colorado and of the 
San Luis Valley in particular. The following statement, showing the 
percentage of silicic acid in the total solids of several waters, is taken 
from his article : 

Percentage of silicic acid in total solids of San Luis Valley waters. 

Alamosa, Bucher well 46. 9 

Alamosa, Spriesterbach well 27. 

Alamosa, McNieland well 36. 

Del Norte, Rio Grande water 27. 15 

Mclntire Springs 29. 64 

After confirmatory experimental treatment of powdered feldspar 
with distilled carbonated water, Headden concludes that the high 
percentage of silicic acid, combined and free, is normal for mountain 
waters in a region in which feldspar is an essential constituent of the 
rocks. 

Perhaps the most noticeable constituent of the colorless waters, 
and to a lesser extent of the tinted waters as well, is sulphur. In 
the form of sulphates, as shown by the analyses, the greatest amount 
of sulphur is contained in the mill well at La Jara and in the Mclntire 
Springs. Lesser amounts are shown by wells at Alamosa and Monte 
Vista and least of all by the tinted waters from the Mosca-Hooper 
district. 

Sulphur is also present in the form of sulphureted hydrogen, which 
may be faintly or decidedly perceptible in most of the well waters 
of the valley, from both great and small depths. Upon oxidation, 
as the water is discharged from the well, the free sulphur is de- 
posited in the stream flowing from the well as a gelatinous white 
precipitate upon vegetation or other objects, which are sometimes 
turned quite black. Occasionally the precipitate shows the long, 
delicate waving filaments of some form of sulphur-secreting bacteria, 
possibly Thiothrix. 

In a single artesian well there was noticed a decided chalybeate 
taste and a reddish flocculent ferruginous precipitate in the stream 
flowing away from the well. This was in lot 1 of sec. 6, T. 43 N., 
R. 8E. 

a Am. Jour. Sci., 4th ser., vol. 16, 1903, pp. 169-184. 
42120°— wsp 240—10 8 



114 THE SAN LUIS VALLEY, COLOEADO. 

In the Mosca-Hooper district the waters are of a yellowish to dull- 
brown tint and have, for the valley, high contents of the alkalies and 
organic matter. These wells often give off gas more or less freely, 
some of them yielding enough to supply a cooking stove. The gas 
and the color are probably due to the decomposition of peaty moss 
which apparently grew in the swampy lake at a low stage. Some of 
the wells which have the deepest tinted waters do not yield gas. 
The water in wells yielding gas is always tinted, but usually only 
slightly so. The gas burns brightly with a yellow flame. It has a 
benzine-like odor, differing in this respect from natural gas elsewhere, 
which has an odor of sulphureted hydrogen. The amount of organic 
matter in the tinted waters, varying from 42 to 134 parts per million, 
is shown in the table of analyses on page 112. 

The artesian water of this area is one of its most valuable assets. 
Cold, palatable, and free from probability of contamination, it must 
continue to be one of the chief factors in the salubrity of the valley. 
The tinted waters of the Mosca-Hooper district have a disagreeable 
taste to one not accustomed to them. The appearance of the water 
resembles that of rain that has collected in a hollow stump, and the 
taste is much what one imagines stump water to have. The slight 
odor of sulphureted hydrogen and the brownish color, together with 
the effect of imagination, are sufficient to explain this likeness, how- 
ever. No case is known of injury from the use of the tinted waters, 
though it seems not unreasonable to suppose that the long-continued 
use of waters charged as highly with alkalies as these would entail 
some bad effect. 

The colorless waters, containing a large percentage of silica (Si0 2 ), 
when used in boilers form considerable scale, which is uniformly 
hard and tough; the tinted waters of the Mosca-Hooper district, con- 
taining less silica but high percentages of the alkaline carbonates, 
when so used are entirely free from scale but foam badly and also 
corrode and pit the boiler tubes. This damage is so great that the 
Denver and Rio Grande Railroad well at Hooper was abandoned for 
boiler use. 

Though containing two to three times as much matter in solution 
as the ditch water, the clear artesian water along the west side of the 
valley is used, and has been for years, without injurious effect for 
irrigation of all crops. The tinted water, however, has a different 
effect. Along the margin of the streams flowing away from these 
wells there is always more or less alkali incrustation, and along 
one such stream, from a well in the NE. | sec. 27, T. 39 N., R. 10 E., 
a strip 10 to 15 feet wide was entirely bare of vegetation and there 
was much alkali along the margins. Reports as to the deleterious 
effects of the use of these waters for irrigation vary widely, as is to 
be expected in view of the fact that the degree to which the water is 



QUALITY OF WATER. 115 

tinted is not a conclusive guide to its alkalinity, inasmuch as it 
depends largely on peaty infusion. Thus some very dark waters may 
not show such injurious effects as a lighter-colored water that has a 
higher content of matter in solution. It seems to be pretty generally 
agreed, however, as the result of experience, that the dark water is 
nowhere as good as the ditch water and that in many places it is 
positively harmful and should always, if possible, be used in conjunc- 
tion with ditch water. Its moderate use is likely to cause a "case- 
hardening" or the formation of a hard crust on the soil surface. In 
any event, even if one application is not injurious its continued use 
in subirrigation will surely impregnate the soil with alkali. 

USES OF THE WATER. 

The principal use of the artesian water is for household purposes, 
and most of the houses, even on many of the remote ranches, 
have running water piped into the kitchen and bathroom. Some 
wells, particularly in Monte Vista, which have not sufficient head to 
force water into the houses, yet flow freely at the ground level, are 
used to operate hydraulic rams, which throw a smaller stream to the 
desired height. 

The artesian water is also especially desirable for stock purposes 
because of its moderate and constant temperature, which is high 
enough so that the wells remain open in winter; because of its con- 
tinuity of supply without pumping or other care; and because of its 
freedom from contamination. Wells are bored here and there over 
the stock ranges in the valley by private persons or by neighborhood 
associations. 

The waste flow from the household wells is either run into irrigating 
ditches or is used for the irrigation of gardens and truck patches. 
In the towns lawns, gardens, and shade trees are irrigated from the 
overflow of the wells. The surplus not so used runs into the gutters 
and is ordinarily collected into a ditch outside the town and used for 
field irrigation. 

In certain sections of the valley the artesian water is an essential 
factor in irrigation. These regions can be recognized on the map by 
the close grouping of the wells and by their alignment in rows, ordi- 
narily on the west side of the tracts of land, for this practice is largely 
confined to the west side of the valley, where the west side of any tract 
is the higher. Areas where many wells have been sunk for this purpose 
are (1) the region between Henry station and Bowen schoolhouse; 
(2) along Rock Creek; (3) in the neighborhood of Veteran school- 
house; and (4) in the Warner neighborhood. In the first of these 
localities the wells were sunk for the purpose of irrigating grain, but 
in the last three chiefly for the purpose of irrigating native hay. 
Native meadows, since they are not cultivated from year to year, 



116 THE SAN LUIS VALLEY, COLORADO. 

have many little irregularities and hummocks which can not be irri- 
gated from ditches. It is customary to irrigate such places, if of 
sufficient area, by a well sunk on the highest point. 

In the Veteran and Warner neighborhoods the wells are used to 
irrigate both grain and hay, and their development was largely the 
result of the failure of ditch water. For the same reason many wells 
have been sunk toward the center of the valley in the Hooper and 
Mosca districts, where the supply of ditch water has been very inade- 
quate in recent years. A recent development of the use of wells for 
irrigation is the construction of about fifty 6-inch wells in the vicinity 
of Henry station and westward as far as the Fountain neighbor- 
hood. These have in general been very successful. 

The average well, if allowed to flow continuously, undisturbed, will 
wet an area of not more than one-half acre around the mouth of the 
well. The greater number of wells are used simply to supplement 
the flow in the ditches. The supply of ditch water early in the season 
is always sufficient to raise the "sub." Then, later in the season, 
when the ditch water fails, the ground being already wet, the steady 
flow of the artesian wells is of great value. Where wells are not to be 
used in connection with the ditch water a reservoir is a necessity, 
unless they are very large. In many parts of the valley, owing to the 
loose texture of the soil, reservoirs will absorb the entire flow of a well 
for a year before holding water. It is suggested that it would be a 
good plan to construct reservoirs in the fall and turn in the muddy 
flood water from the ditch until the bottom of the reservoir is thor- 
oughly wetted and silted up. 

It is hard to make a just estimate of the extent of the use of artesian 
water in irrigation, first, because of the fact, before stated, that the 
water is in many places turned into the ditches to supplement the 
ditch flow, and, second, because there is a tendency in the valley to 
underrate the extent of such use, lest an optimistic estimate should 
unfavorably affect desired legislation for storage reservoirs in the 
mountains. It is realized locally that further agricultural expansion 
depends on the construction of reservoirs to conserve the flood waters, 
and there is a concerted movement in" that direction. 

WELLS. 

WELL DRILLING. 

With a few exceptions the wells of the valley have been sunk by 
the hydraulic jet process. The exceptions are those which have been 
drilled through lava, mostly nonflowing wells. The deepest well in 
the valley, the No. 1 well of the San Luis Oil Company, 1,283 feet 
deep, was sunk by the hydraulic process, as were many others that 
reach 1 ,000 feet or more in depth. The individual drillers have their 
favorite forms of bits, and their own methods of "rotating" or 



WELL DKILLING. 117 

"driving" the casing, but the general method of sinking is the same 
here as elsewhere. 

When the well has been sunk into the desired aquifer and the flow 
is reached, the pump is kept going for some time, a day or more in 
deep wells, with the object of stirring up 1 the sand and carrying it up 
the well bore until a considerable cavity is made at the bottom of the 
well. Water can be delivered to the well only so fast as it can come 
through the sand walls of the cavity at the bottom of the well. The 
larger this cavity, the greater the contributing area of sand wall 
and the greater the volume of water. A new well naturally excavates 
for itself such a cavity and "throws sand" for several days, often 
with a pronounced increase of flow. But in the process large lumps 
may cave away from the clay above and entirely shut off the flow. 
It is the better plan, therefore, to pump out the cavity while the drill 
rig is set up over the well, so as to clear away the obstruction if the 
well chokes up. It is customary in the valley to case only to the first 
clay bed, through the superficial soil and gravel. This distance 
varies from 10 to 50 or rarely to 100 feet. Though inevitable, this 
practice of partial casing is much to be deplored. 

Owing to the high freight rates, the item of casing in an average 
well costs more than the drilling. As long as a new well can be put 
down for the cost of casing the first one, most people of moderate 
means, at least in districts where the clay resists the caving fairly well, 
will prefer to take chances on the caving of the uncased well, espe- 
cially where the wells are drilled for irrigation purposes as a last resort 
after successive failures of the ditch water and when immediate results 
are needed. Many wells, however, are cased down to the main flow 
that is used. The flow of such a well is affected only by increase in the 
number of wells, and can be shut off in winter time with impunity, 
whereas the uncased well is quite likely to cave within a year or so, 
particularly if plugged in winter. A large percentage of the wells in 
the valley have fallen off one-half or more in flow, principally through 
caving in. If caving takes place as a result of plugging the well, it 
usually happens when the plug is removed. While the well is open 
the rapid ascent of the water tends to carry to the surface and clear 
the well of any caved material as fast as it falls. When the well is 
plugged, however, the water in the bore and to a certain extent in the 
different aquifers assumes a uniform pressure. This uniformity of 
pressure has a tendency to favor the disintegration of the walls of the 
bore. The material breaking away settles downward through the 
still water in the bore and packs itself in the bottom. When the well 
is turned on again the amount of material packed in the bottom may 
be sufficient to cut off the lower flow. Again, the sudden shock of 
decrease of pressure when the well is suddenly opened by knocking 
out the plug has likewise a tendency to jar off pieces of the clay wall. 



118 THE SAN LUIS VALLEY, COLOKADO. 

The cost of boring wells, owing to the similarity of the formations, 
is nearly uniform for similar sizes over the valley. The price of the 
completed well varies of course with the diameter and depth of the 
bore hole and the size and length of the casing. The price of casing 
also varies materially from time to time. The following statement 
gives the cost of a few typical wells in Alamosa, and the cost of others 
has been given in preceding pages. 

Cost of typical wells in Alamosa. 

Two-inch wells: 

230 feet deep, eased about 50 feet $55 

460 feet deep, cased about 50 feet 101 

600 feet deep, cased about 50 feet 135 

735 feet deep, cased to the bottom 351 

Three-inch wells: 

650 feet deep, cased about 50 feet 145 

730 feet deep, cased about 50 feet 161 

Town well, 5f inches in diameter: 

865 feet deep, cased to 852 feet 1, 865 

APPROXIMATE MEASUREMENT OF FLOWING WELLS. 

Tables for determining the discharge of water from completely 
filled vertical and horizontal pipes were prepared a number of years 
ago by Prof. J. E. Todd, state geologist of South Dakota, who issued 
a private bulletin describing simple methods of determining quickly, 
with fair accuracy and with little trouble, the yield of artesian wells. 
The following tables and explanations relating to vertical and hori- 
zontal pipes are taken from this bulletin, with extensions by the 
present writer. The explanations and tables relating to the meas- 
urement in the partly filled horizontal and inclined pipes are from a 
paper by Charles S. Slichter. a 

PLOWS FROM FILLED PIPES. 

In determining the flow of water discharged through a pipe of 
uniform diameter all that is necessary is a foot rule, still air, and care 
in taking measurements. Two methods are proposed, one for pipes 
discharging vertically, which is particularly applicable before the 
well is permanently finished, and one for horizontal discharge, which 
is the most usual way of finishing a well. 

The table on page 121 is adapted to wells of moderate size as well 
as to large wells. If the well is of a diameter not given in the table 
its discharge can without much difficulty be obtained from the table 
by remembering that, other things being equal, the discharge varies 
as the square of the diameter of the pipe. If, for example, the pipe 

a In Contributions to the hydrology of the eastern United States, 1904: Water-Supply Paper TJ. S. 
Geol. Survey No. 110, 190.5, pp. 37-42. 



APPROXIMATE MEASUREMENT OF FLOWING WELLS. 



119 



is one-half inch in diameter its discharge will be one-fourth of that 
of a pipe 1 inch in diameter for a stream of the same height. In a 
similar manner the discharge of a pipe 8 inches in diameter can be 
obtained by multiplying the discharge of the 4-inch pipe by 4. 

In the first method the inside diameter of the pipe should first be 
measured, then the distance from the end of the pipe to the highest 
point of the dome of the water above, in a strictly vertical direction — 
a to Z> in the diagram (fig. 14). Find these distances in Table 1; the 
corresponding figure gives the number of gallons discharged each 
minute. Wind would not interfere in this case, if only the measure- 
ments are taken vertically. 

The method for determining the discharge of horizontal pipes 
requires a little more care. First measure the diameter of the pipe 
as before; then from a point (b, fig. 14) 6 inches vertically below the 




10 inches 
71. 7 gallons 
per minute 




Hi I'M 'I 

I'll il'l'l 1 



Figure 14. — Diagram illustrating flow from vertical and "horizontal pipes. 



center of the opening of the pipe, or some convenient point corre- 
sponding to it on the side of the pipe (a), measure strictly horizontally 
to the center of the stream (b to e). With these data the flow in 
gallons per minute can be obtained from Table 2. It will readily be 
seen that a slight error may make much difference in the result. 
Care must be taken to measure horizontally and also to the center 
of the stream. Because of this difficulty it is desirable to check the 
first determination by a second. For this purpose columns are given 
in the tables for corresponding measurements from a point 12 inches 
below the center of the pipe. Of course the same result should be 
obtained in the two measurements of the same stream. Wind blow- 
ing either with or against the water may vitiate results to an indefi- 



120 THE SAN LUIS VALLEY, COLORADO. 

nite amount; therefore measurements should be taken while the air 
is still. 

Whenever fractions occur in the height or horizontal distance of the 
stream the number of gallons can be obtained by apportioning the dif- 
ference between the readings in the table for the nearest whole num- 
bers, according to the size of the fraction. For example, if the distance 
from the top of the pipe to the top of the stream in the first case is 
9 1 inches, one-third of the difference between the reading in the table 
for 9 and 10 inches must be added to the former to give the correct 
result. 

One might suppose that when the flow of a well is measured by 
both methods the results should agree, but that is not the fact. In 
the vertical discharge there is less friction, and the flow is larger; so 
also in the second method differences will be found according to the 
length of the horizontal pipe used. 

As pipes are occasionally set at an angle, it is well to know that the 
second method can be applied to them if the first measurement is 
taken strictly vertically from the center of the opening, and the sec- 
ond measurement from that point parallel with the axis of the pipe to 
the center of the stream, as before. The rates of flow in Table 2 are 
then applicable. 

These tables are based upon a well-known formula of hydraulics. 
Experiment has shown that a margin of error is involved in the 
estimates when the height of the jet is less than 2 feet — that in such 
results there is 5 to 20 per cent or more of excess, which is greater 
the smaller the pipes and the lower the jets. But these are just the 
flows that can be most easily measured in a vessel of known size, and 
this method should always be resorted to when possible. The greater 
number of the larger wells flow from vertical pipes. Such a pipe may 
be so close to the ground that the water can not be caught in a 
receptacle; and not uncommonly it is surrounded by a reservoir, 
designedly or otherwise, so that it is inconvenient to measure by 
means of a vessel. For measuring the flow of such wells the tables 
will be found very convenient. 

To convert gallons into cubic feet, divide by 7.5, or, more accu- 
rately, by 7.48. 

A second-foot equals a flow of 448.8 gallons a minute, or 38.4 Colo- 
rado miner's inches. A. flow of 100 Colorado miner's inches equals 
2.6 second-feet. A flow of 100 Colorado miner's inches equals 1,170 
gallons a minute; 1 Colorado miner's inch equals 1 1.7 gallons a minute. 



APPROXIMATE MEASUREMENT OF FLOWING WELLS. 



121 



Table 1. — For determining yield of artesian wells flowing from vertical pipes. 
[Gallons per minute.] 







Yield from pipe with diameter of— 




Height 














of jet. 


1 inch. 


2 inches. 


3 inches. 


4 inches. 


5 inches. 


6 inches. 


In. 














i 


1.90 


6.7 


15.2 


29.4 


47.2 


60.8 


i 


2.80 


10.7 


24.0 


43.0 


69.2 


96.0 


§ 


3.43 


13.6 


30.4 


54.0 


85.5 


121.6 




3.96 


15.8 


35.6 


63.2 


98.8 


142.4 


j 


4.42 


17.8 


40.2 


71.0 


110.8 


160.8 




4.85 


19.5 


44.3 


78.0 


121.6 


177.2 


i 


5.24 


21.1 


48.0 


84.1 


130.5 


192.0 


1 S 


5.60 


22.4 


51.4 


89.6 


140.0 


205.6 


1J 


6.29 


25.2 


57.4 


100.5 


156.8 


229.6 


14 


6.90 


27.6 


62.6 


110.2 


171.6 


250.4 


if 


7.45 


29.9 


-67.5 


119.4 


186.3 


270.0 


2 


7.99 


32.0 


71.9 


128.0 


200.0 


287.6 


3 


9.81 


39.2 


88.3 


146.8 


245. 


353.2 


4 


11.33 


45.3 


102.0 


181.2 


283.1 


408.0 


5 


12.68 


50.7 


113.8 


202.8 


316.9 


455.2 


6 


13.88 


55.5 


124.9 


222.0 


346.9 


499.6 


7 


14.96 


59.8 


134.9 


239.2 


373.8 


539. 6 


8 


16.00 


64.0 


144.1 


256.0 


400.0 


576.4 


9 


17.01 


68.0 


153.1 


272.0 


425.0 


612.4 


10 


17. 93 


71.6 


161.3 


286.4 


447.5 


645.2 


11 


18.80 


75.2 


169.3 


300.8 


470.0 


677.2 


12 


19.65 


78.6 


176.9 


314.4 


491.3 


707.6 


13 


20.46 


81.8 


184.1 


327.2 


511.3 


736.4 


14 


21.22 


84.9 


190.9 


339.6 


530.6 


763.6 


15 


21.95 


87.8 


197.5 


351.2 


548.8 


790.0 


16 


22.67 


90.7 


203.9 


362.8 


566.9 


815.6 


17 


23.37 


93.5 


210.3 


374.0 


584.4 


841.2 


18 


24.06 


96.2 


216.5 


384.8 


601.3 


866.0 


19 


24.72 


98.9 


222.5 


395.6 


618.1 


890.0 


20 


25.37 


101.6 


228.5 


406.4 


635.0 


914.0 


21 


26.02 


104.2 


234.3 


416.8 


651.3 


937. 2 


22 


26.66 


106.7 


240.0 


426.8 


666.9 


960.0 


23 


27.28 


109.2 


245.6 


436.8 


682.5 


482.4 


24 


27.90 


111.6 


251.1 


446.4 


697.5 


1,004.4 


25 


28. 49 


114.0 


256.4 


456.0 


715.5 


1,025.6 


26 


29.05 


116.2 


261.4 


464.8 


726.3 


1,045.6 


27 


29.59 


118.2 


266.1 


472.8 


738.8 


1,064.4 


28 


30.08 


120.3 


270.4 


481.2 


751.9 


1,081.6 


29 


30.55 


121.9 


274.1 


487.6 


761.9 


1,096.4 


30 


30.94 


123.4 


277.6 


493.6 


771.3 


1,110.4 


36 


34.1 


136.3 


306.6 


545.2 


851.9 


1,226.4 


48 


39.1 


156.5 


352.1 


626.0 


978.1 


1,408.4 


60 


43.8 


175.2 


394.3 


700.8 


1,095.0 


1,577.2 


72 


48.2 


192.9 


434.0 


771.6 


1, 205. 6 


1,736.0 


84 


51.9 


207.6 


467.0 


830.4 


1,297.5 


1,868.0 


96 


55.6 


222.2 


500.0 


888.8 


1,388.8 


2,000.0 


108 


58.9 


235.9 


530.8 


943.6 


1,474.4 


2, 123. 2 


120 


62.2 


248.7 


559.5 


984.8 


1,554.4 


2,238.0 


132 


65.1 


260.4 


585.9 


1,041.6 


1,627.5 


2, 343. 6 


144 


68.0 


272.2 


612.5 


1,088.8 


1,701.3 


2,450.0 



122 



THE SAN LUIS VALLEY, COLORADO. 



Table 2. — For determining yield of artesian ivells flowing from horizontal pipes. 

[Gallons per minute.] 



o o 


l-inci 


pipe. 


2-incb 


pipe. 


3-ineb 


pipe. 


6-inch 


12-inch 


6-inch 


12-inch 


6-inch 


12-inch 


a a 
,2 


level. 


level. 


level. 


level. 


level. 


level. 


In. 














6 


7.01 


4.95 


27.71 


19.63 


62.35 


44.17 


7 


8.18 


5.77 


32.33 


22.90 


72.74 


51.53 


8 


9.35 


6.60 


36.94 


26.18 


83.12 


58.91 


9 


10.51 


7.42 


41.56 


29.45 


93.51 


66.26 


10 


11.68 


8.25 


46.18 


32.72 


103. 91 


73.62 


11 


12.85 


9.08 


50.80 


35.99 


114. 30 


80.98 


12 


14.02 


9.91 


55.42 


39.26 


124. 70 


88.34 


13 


15.19 


10.73 


60.03 


42.54 


135. 07 


95. 72 


14 


16.36 


11.56 


64.65 


45.81 


145. 46 


103. 07 


15 


17.53 


12.38 


69.27 


49.08 


155. 86 


110. 43 


16 


18.70 


13.21 


73.89 


52.35 


166. 25 


117. 79 


17 


19.87 


14.04 


78.51 


55.62 


176. 65 


125. 15 


18 


21.04 


14.86 


83.12 


58.90 


187. 02 


132.53 


19 


22.21 


15.69 


87.74 


62.17 


197. 42 


139. 88 


20 


- 23. 37 


16.51 


92.36 


65.44 


207. 81 


147. 24 


21 


24.54 


17.34 


96.98 


68.71 


218. 21 


154.60 


22 


25.71 


18.17 


101. 60 


71.98 


228. 60 


161.96 


23 


26.88 


18.99 


106. 21 


75.26 


238. 97 


169. 34 


24 


28.04 


19.82 


110. 83 


78.53 


249. 37 


176. 69 


25 


29.11 


20.64 


115.45 


81.80 


259. 76 


184. 05 


26 


30.38 


21.47 


120. 07 


85.07 


270. 16 


191.41 


27 


31.55 


22.29 


124. 69 


88.34 


280. 55 


198. 77 


28 


32.72 


23.12 


129. 30 


91.62 


290. 93 


206. 15 


29 


33.89 


23.95 


133. 92 


94.89 


301. 32 


213. 50 


30 


35.06 


24.77 


138. 54 


98.16 


311. 72 


220. 86 


31 


36.23 


25. 59 


143. 16 


101.43 


322. 11 


228. 22 


32 


37.40 


26.42 


147. 78 


104. 70 


332. 51 


235. 58 


33 


38.57 


27.25 


152. 39 


107. 98 


342. 88 


242. 96 


34 


39.64 


28.08 


157.01 


111.25 


353. 27 


250. 31 


35 


40.45 


28.64 


161.63 


114.52 


363. 67 


257. 67 


36 


41.60 


29.46 


166.25 


117.79 


374. 06 


265. 03 


Contir 


ue l>y add 


ing for eac 


h inch — 










1.15 


0.82 


4.62 


3.27 


10. 39 


7.36 



The flow in pipes of diameters not given in the table can easily be 
obtained in the following manner: 

For J-inch pipe, multiply discharge of 1-inch pipe by 0. 25 

For f -inch pipe, multiply discharge of 1-inch pipe by 0. 56 

For l|-inch pipe, multiply discharge of 1-inch pipe by 1. 56 

For 1 J-inch pipe, multiply discharge of 1-inch pipe by 2. 25 

For 3-inch pipe, multiply discharge of 2-inch pipe by 2. 25 

For 4-inch pipe, multiply discharge of 2-inch pipe by 4. 00 

For 4|-inch pipe, multiply discharge of 2-inch pipe by 5. 06 

For 5-inch pipe, multiply discharge of 2-inch pipe by 6. 25 

For 6-inch pipe, multiply discharge of 2-inch pipe by 9. 00 

For 8-inch pipe, multiply discharge of 2-inch pipe by 16. 00 

MEASUREMENT OF FLOWS FROM PARTLY FILLED PIPES. 

From Table 3 below it should be possible, if the wind is not blowing 
too hard, to determine the flow from a partly filled pipe with an error 
probably not exceeding 10 per cent. This error is no greater than the 
fluctuation of the flow due to the daily variations of the barometric 
pressure in most wells. The results in extreme cases, such as a 



APPEOXIMATE MEASUREMENT OF FLOWING WELLS. 



123 



J-inch stream in a 6-inch pipe are, of course, still less accurate, and 
actual measurement hy collecting the water in a vessel of definite 
capacity should be resorted to if possible. 

Table 3. — For estimating the discharge from partly filled horizontal or sloping pipes. 



Fractional part 




Fractional part 




of diameter of 


Discharge ex- 


of diameter of 


Discharge ex- 


pipe not occu- 


pressed as per- 


pipe not occu- 


pressed as per- 


pied by water. 


centage of dis- 


pied by water. 


centage of dis- 


[Obtained by- 


charge from 


[Obtained by 


charge from 


dividing A D 


full pipe, 


dividing A D 


full pipe, 


by A B in 


same size. 


by A B in 


same size. 


fig. 1.] 




fig. 1.] 




0.05 


0.9S 


0.55 


0.44 


.10 


.95 


.60 


.37 


.15 


.91 


.65 


.31 


.20 


.86 


.70 


.25 


.25 


.80 


.75 


.20 


.30 


.75 


.80 


.14 


.35 


.69 


.85 


.092 


.40 


.63 


.90 


.054 


.45 


.55 


.95 


.015 


.50 


.50 


1.00 


.000 



To estimate the discharge from a partly filled horizontal or sloping 
pipe, first estimate the discharge from full pipe of the same size by 
means of Table 2. 







Figuee 15.— Method of measuring partly filled pipes. 

Next measure with a foot rule the dimension A D (fig. 15) of the 
empty portion of the cross section of the pipe. Divide this by the 



124 THE SAN LUIS VALLEY, COLOEADO. 

inside diameter of the pipe, which will give the fractional part of the 
diameter that is occupied by the empty part of the pipe. In Table 3 find 
in the first column the number nearest to the above quotient. Oppo- 
site this number will be found the percentage of the discharge of the 
full pipe that the partly filled pipe is yielding. It is sufficient to 
measure the distance A D to the nearest eighth of an inch, or at most 
to the nearest sixteenth of an inch. 

Suppose that a 2-inch horizontal pipe has a length of jet of 13 inches 
at 6-inch level. From Table 2 this would represent a discharge of 60 
gallons per minute from the full pipe. Suppose that the distance 
A D is five-eighths of an inch and A B is 2 inches, or sixteen-eighths 
of an inch. Dividing 5 by 16 gives 0.31. In the first column of Table 
3 we find 0.30, the nearest to 0.31, and opposite 0.30 in the second 
column of the table appears 0.75. The discharge from the partly 
filled pipe is therefore 60 X 0.75 = 45 gallons per minute. 



INDEX. 



A. Tage. 

Acknowledgments to those aiding 7-8 

Adams ranch well, description of 61-62 

record of 61 

Agriculture, conditions of 25-29 

Alamosa, wells at and near 55, 57-60 

wells at and near, location of, map show- 
ing 58 

records of 58-60 

water of, analyses of 112, 113 

AlamosafCreek, fan of 10 

glaciation on 33 

reservoir on 18 

valley of, geology of 30-31 

section of • . . . 31 

view on-. '. 30 

Alamosa formation, age of 46 

deposition of 52-53 

fossils of 47 

occurrence and character of 40-47 

sections of 40-43 

view of 40 

Alamosa Milling and Elevator Co.'s well, 

description of 59 

water of, analysis of 112 

Alkali, injury from 26, 27-28 

location of, map showing, character of. . . 28 
Alkali-lake deposits, occurrence and character 

of 50 

Alluvial fans. Sec Fans, alluvial. 

Alluvium, occurrence and character of 49 

Altitudes, table of 11-12 

Ammonia, amount of, in well waters Ill 

Andersen well, description of 83-84 

water of, analysis of 112 

Antelope Springs, description of 103 

Antonito, view near 30 

wells near 92-93 

records of 92-93 

water of, analysis of 112 

Artesian basin (San Luis), capacity of 56-57 

characteristics of 105-110 

description of 54-55 

water of, source of 55-56 

supply of 56 

Artesian system, general requisites of 54 

Atkinson ranch well, description of 68 

Austin ranch well, description of 68 

B. 

Baca grant, wells on 79, 100 

Baldy, wells near 100-101 

Baldy Peak, rocks of and near 35-36 

Bear Creek, glaciation on 38 

Becker well, description of 67 

record of ......... ^. .„.,..,.. . 67 



Page. 

Beckwith well, description of 101 

record of 101 

Bibliography of region 8-9 

Black Canyon, glaciation on 38 

Blanca farm well, description of 60 

water of, analysis of 112 

Blanca Peak, fans near 10 

glaciation on 38 

rocks of 35-36 

section from, figure showing 45 

view of 10 

Bluffs, occurrence of 11 

Bowen, wells near 97-98, 115 

wells near, record of 97 

Braiden well, description of 94 

Bucher well, description of 55, 57 

water of, analysis of 111,112,113 

view of 40 

Building stone, occurrence and character of. . 30 

C. 

Calkins wells, description of 80 

records of SO 

Capulin, wells near 95-97 

wells near, records of 95, 90 

Carnero, wells near 74 

Carpenter, L. G., cited 49,56,57-58 

Cat Creek, fan of 10 

glaciation on 33 

valley of, geology of 31 

view on 32 

Centennial ditch, flow of 19 

Center, wells near 71-73 

wells near, location of, map showing 72 

record of 73 

water of, salts in Ill 

Chamberlain Hot Springs, description of... 103-104 

pumping near 21 

view at 102 

Chauvenet, R., analysis by 112 

Chicago and San Luis Oil Co.'s well, descrip- 
tion of 82 

record of 43 

Chitton wfell, record of 84 

Clark well, description of 87-88 

gas in 87 

record of 88 

view at 88 

Climate, description of 22-25 

Colorado, index map of 9 

Conejos, rainfall and temperature at 22-24 

Conejos County Oil Co.'s well, description of. 95 

record of 95 

Conejos Range, geology of 29-34 

section from, figure showing 45 

125 



126 



INDEX. 



Conejos River, fan of 10-11 

springs on 101-102 

Costilla ditch, flow of 19 

Crestone, wells near , 100 

Crops, character of 26-27 

Cross, Whitman, work of 30 

Culebra Range, glaciation in 38 

rocks of 37 



D. 

Dall, W. H., fossils identified by 

Davidson well, description of 

Dead Man Creek, well on 

Dearborn Drug & Chemical Co., analyses by. 



47 
78 
100 
112 



Del Norte, discharge at 13, 16, 20 

wells near 98 

water of, analysis of 113 

Del Norte canal, flow of 10, 19 

Denver and Rio Grande wells, description of. 58, 

76,86,93 

record of 58, 86, 93, 100 

water of, analysis of 112 

Dexter Spring, description of 102 

water of, analysis of 111,112 

Drainage, description of 12 

Dunn ranch well, description of 99 

E. 

East ranges, glaciation of 37-38 

stratigraphy and structure of 36-37 

Elevations, table of 11-12 

Elliott well, water of, salts in Ill 

Embudo, discharge at 14, 16-18 

Emmons, S. F., cited 35 

Empire canal, flow of 19 

Empire farm wells, description of 60-61 

records of 61 

view of 60 

Endlich, F. M., cited 36-37,39-40,48,49,53 

Engle, N. Mex., reservoir at 19 

Eskridge well, record of 96 

Espinosa well, description of , 74 

view of 74 

F. 

Fans, alluvial, occurrence of 10, 48-49 

relation of, to moraines 46 

figure showing 46 

relation of, to water beds 45-46 

Farmers' Union canal, flow of 10, 19 

Fellows, A. L., cited 17 

Field work, date of '. 7 

Fleck, Herman, cited 50 

Flow, variations in 105-108 

Flowing wells, detailed descriptions ofr 57-92 

Flumes, canvas, use of 21-22 

Fort Garland, rainfall and temperature at. . . 22-25 

rocks near 39 

wells near 101 

record of 101 

Fort Massachusetts, rainfall at 25 

Fountain, wells near 62-63 

wells near, records of 62-63 

Fowler, Jacob, cited 52 

Frazee ranch well, description of 77 

Fred well, record of 96 

Fritz Emperius well, description of 59 



G. Page. 

Gaging stations, location of 12-13 

Garnett, rainfall and temperature at 22-24 

Garrison Mill and Elevator Co.'s well, descrip- 
tion of 85 

record of 85 

water of, analysis of 112 

Gas, occurrence of 81-82 

Geography, description of 9-29 

Geologic history, outline of 50-54 

Geology, description of 29-54 

Glaciation, occurrence and character of: 

relation of, to fans 46 

figure showing 46 

Goodall well, description of 59 

record of 59 

H. 

Hansen Bluff, description of 11 

section at 40-41 

view of 40 

Hansen ranch well, description of 67 

Harvey ranch well, description of 96-97 

Hayden, F. V., cited 32-33, 36, 39, 48 

Headden, W. P., analysis by 112 

cited 50, 111 , 113 

Henry, wells near 60-62, 115 

wells near, records of 61-62 

Hess well, description of. 73 

record of 73 

Hinton, R. J., cited 49 

Hirst well, description of 59 

Hooper, wells near, location of, map showing. 85-88 

records of 85-86, 88 

water of, analyses of 112 

Hot Creek Springs, description of 104 

Hubbard well, description of 63 

record of 63 

Hunt Springs, description of 102-103 

view of 88 

Hydrography, description of 12-22 

I. 

Irrigation, extent of 19-22 

methods of 27-29 

progress of 25-26 

relation of, to Rio Grande 15-18 

use of wells for 56-57, 115-116 

See Subirrigation. 

J. 

Jacobs ranch, description of 89-90 

gas on 90 

Johansen ranch well, description of 69 

Johnston well, description of 74 

record of 74 

Jordan well, description of 99 

K. 

Kennicott Water Softener Co., analysis by. . . 112 

Kinch well, description of 62 

record of 62 

view of 60 

Kinney ranch, wells on 88-89 

Knapp well, description of 95 

record of 95 



INDEX. 



127 



L. Page. 

La Garita, wells near 99 

La Jara, rainfall and temperature at 22-24 

wells near, description of 63-65 

location of, maps showing 64, 65 

records of 63, 65 

water of, analysis of 112 

La Jara.Creek, fan of 10 

La Jara Milling and Elevator Co.'s well, de- 
scription of 64 

water of, analysis of 112 

Lambert well, description of 64-65 

record of 65 

Lavas, effusion of 51,53-54 

Lee, W. T., cited 34,37,53 

Literature, list of 8-9 

Location of San Luis Valley 9 

map showing 9 

Lockett, wells of 73-74 

wells of, records of , 73, 74 

Los Mogotes, discharge near 15 

Los Sauces, springs at, water of, analyses of. . 112 

wells near 67-68 

records of : . . . 67 

Lovett well, record of 96 

M. 

McDaniel well, description of 94 

record of 94 

Mclntire Springs, description of 101-102 

flow of 17 

view at 102 

water of, analysis of 111,112,113 

McNieland well, water of, ammonia in Ill 

water of, silicic acid in 113 

Manassa, wells near 93-95 

wells near, records of 94 , 95 

Map, index, of Colorado 9 

Map of San Luis Valley Pocket. 

description of 10 

Medano ranch, dunes on, view of 48 

wells on, description of 80 

Medano Springs, description of 103 

Mirage, wells near 78 

Mitchell ranch well, description of 61 

Moffat, wells near 76-77 

wells near, location of, map showing 77 

records of 77 

water of, analysis of 112 

Monte Vista, rainfall and temperature at 22-24 

rocks near 32 

wells near 69-71,98 

location of, map showing 70 

record of 69, 71 

water of, analysis of 111,112 

Monte Vista canal, flow of 19 

Monte Vista Milling Co.'s well, description of. 69 

record of 69 

water of, analysis of 112 

Mosca, wells near 82-85 

wells near, location of, map showing 83 

record of 84 

water of, analyses of - 112 

Mosca-Hooper region, oil and gas in 81-82 

water of, character of 81-82, 114 

effects of 114-115 

wells of 81-90 



Page. 
Mosca Milling and Elevator Co.'s well, de- 
scription of 83 

water of, analysis of 112 

Mosca Pass, sand dunes near 40 

Myers well, description of 67 

record of 67 

N. 

Nash well, description of 79 

record of 79 

Navin ranch well, description of 74 

view of 74 

Newcomb ranch well, record of 41-42 

Newcombe well, description of 96 

Newsom ranch wells, description of 60 

record of 60 

Norland well, description of 64 

O. 

Oil, occurrence of 82 

Orient, springs at, water of, analysis of 112 

Ottaway well, description of 62 

record of 62 

Outcault well, description of 69 

P. 

Painted Rock Bluff, description of 31 

view of 32 

Palmer ranch wells, description of 95 

Parma, wells near 68-69 

wells near, record of 68 

Parrish wells, description of 91-92 

record of 92 

Pipes, flow from 118-124 

Pitzer ranch well, description of 100 

Powell, J. W., on Colorado irrigation 15-16 

Population, character of 25-26 

Prairie ditch, flow of 10, 19 

Precipitation, records of 22-25 

Pumping plants, plan of, figure showing 21 

use of 20-21 

Q. 

Quality of water, records of 111-115 

Quaternary deposits, occurrence and char- 
acter of 47-50 

R. 

Rainfall, records of 22-25 

Recent deposits, occurrence and character of. . 47-50 

Relief, description of 10-12 

Reservoirs, natural, occurrence of 18 

Reservoir sites, occurrence of 18-19 

Richfield, wells near,loeation of, map showing. 05 

Rio Grande, course of 49 

discharge of, at Del Norte 13, 16, 20 

at Embudo 14,16-18 

at State Bridge 14, 16-17 

near Los Mogotes 15 

effect of San Luis irrigation on 15-18 

fan of 10,45-46 

irrigation from 20 

loss of water in sands of 15, 55 

reservoirs on 18-19 

water of, silicic acid in 113 

temperature of 109 



128 



INDEX. 



Rock Creek, cirque on, view of 10 

glaciation on 33 

valley of, geology of 31-32 

wells in 71, 115 

Russell Springs, description of 102 

S. 

Salts, total of, in well waters Ill 

Sand dunes, occurrence of 40, 47-48 

view of 48 

Sanford, wells near 66-67 

wells near, location of, map showing 66 

record of - 67 

Sangre de Cristo Range, age of 53-54 

rocks of - 34-37 

San Isabel, wells near 78-79 

wells near, record of 79 

San Luis, rainfall and temperature at 22-24 

rocks near .' 37 

wells near 90-92 

location of, map showing 90 

San Luis canal, flow of 19 

San Luis Creek, drainage of 12 

fan of 11 

valley of, section of 44-46 

section of, figure showing 45 

San Luis Hills, location of 9 

rocks of 3S-39 

San Luis Oil Co., well of 116 

San Pedro Mesa, rocks of 32,38,39 

Santa Fe formation, deposition of 51-52 

occurrence and character of 32-33, 39-40 

view of 30 

Saguache, rainfall and temperature at 22-24 

rocks near 32 

wells near . , 99 

Saguache Creek, fan of 11 

Sawatch Range, geology of 29-34 

Schwartz ranch well, description of 60 

Seasons, variation of flow with 105 

variation of temperature with 110 

Settlement, order of 25-26 

Shellabarger well, description of 77 

Silicic acid, percentage of, in well waters 113 

Slichter, C. S., cited 118 

Smith well, description of 91 

record of 91 

Soda Lake, view of , 32 

Sodium carbonate, deposits of 50 

Soil, exhaustion of 25-26 

Spriesterbach well, description of 59 

record of 41 

water of, silicic acid in 113 

Spring Creek, description of 102 

Springs, occurrence of 38, 101-104 

supply from 17-18 

Star ranch well, description of 88 

State bridge, discharge near 14, 16, 17 

Stevenson, J. J., cited 52-53 

Stewart ranch well, description of 68 

Stock raising, progress of 27 

Strauss well, description of 98 

Steam gagings, results of 12-15 

"Sub." See Subirrigation. 

Subirrigation, injurious effects of 27-29 



Subirrigation, methods of 27 

pumping for 20 

relation of, to well flow 105 

Sulphur, occurrence of, in well water 113 

Swede Corners, wells near 75-76 

wells near, records of 75 

T. 

Temperature of air, records of 22-23 

Temperature of well water, variations in . . 108-110 
Tinted water. See Mosca-Hooper region. 

Tobler well, description of 78 

Todd., J. E., on flow of wells 118 

Topography, description of 10^12 

U. 

Underflow, pumping of 20-21 

Underground waters, account of 54-116 

Ute Creek, fan on 39 

rocks on 36 

V. 
Valley, rocks of 39-50 

Valley View Hot Springs, description of 104 

water of, analysis of 112 

Van Diest, E. C. and P. H., cited 37 

Vegetation, character of 26 

Veteran, wells near 74, 115-116 

Villa Grove, rocks near 34 

wells near 99-100 

Von Schultz & Low, analyses by 112 

W. 
Wagon Wheel Gap, rainfall and temperature 

at 22-25 

Warner, wells near 76, 115-116 

wells near, section of 76 

Washington Springs, description of 103 

Waters, underground, account of 54-116 

Watson well, description of 85 

A record of 85 

Wells, casing of 117 

drilling of 116-118 

cost of 118 

failure of 105-107 

flow of 105-108 

measurement of 118-124 

grouping of 105 

interference of 106-107 

irrigation from 56-57, 115-116 

water of, quality of 111-115 

temperature of 108-110 

uses of 115-116 

See also particular wells; Flowing wells; 
Nonflowing wells. 

Western ranges, glaciation in 33-34 

rocks of 29-32 

age of 32-33 

See also Conejos Range; Sawatch Range. 

Wilkins well, description of 60 

Willow Creek, park on, view of 34 

rocks on 35 

view on 36 

Worcester ranch well, description of 60 

Woodhouse well, description of 74 



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